Предмет: Математика,
автор: kustikyoi
1.Выполни действия
а)5\9+7\8
в)9\10-(3\5+1\6)+2\3
б)9\20-5\12
2.Реши уравнение
(x - 4\5)+1\30=1\6-1\10
(Остальное в фотографиях) Пожалуйста срочно надо! 46 баллов)
Приложения:
![](https://files.topotvet.com/i/b1a/b1a9cc4876c6b26f97b17205f9716e88.jpg)
![](https://files.topotvet.com/i/5d7/5d7d85f82d1726a9d9673a32a6e84c46.jpg)
Ответы
Автор ответа:
2
II вариант.
1. а)
![\frac{3}{4} + \frac{2}{5} = \frac{3 \times 5}{4 \times 5} + \frac{2 \times 4}{5 \times 4} = \frac{15 + 8}{20} = \frac{23}{20} = 1 \frac{3}{20} = 1.15 \frac{3}{4} + \frac{2}{5} = \frac{3 \times 5}{4 \times 5} + \frac{2 \times 4}{5 \times 4} = \frac{15 + 8}{20} = \frac{23}{20} = 1 \frac{3}{20} = 1.15](https://tex.z-dn.net/?f=+%5Cfrac%7B3%7D%7B4%7D+%2B+%5Cfrac%7B2%7D%7B5%7D+%3D+%5Cfrac%7B3+%5Ctimes+5%7D%7B4+%5Ctimes+5%7D+%2B+%5Cfrac%7B2+%5Ctimes+4%7D%7B5+%5Ctimes+4%7D+%3D+%5Cfrac%7B15+%2B+8%7D%7B20%7D+%3D+%5Cfrac%7B23%7D%7B20%7D+%3D+1+%5Cfrac%7B3%7D%7B20%7D+%3D+1.15)
б)
![\frac{11}{20} - \frac{8}{15} = \frac{11 \times 3}{20 \times 3} - \frac{8 \times 4}{15 \times 4} = \frac{33 - 32}{60} = \frac{1}{60} \frac{11}{20} - \frac{8}{15} = \frac{11 \times 3}{20 \times 3} - \frac{8 \times 4}{15 \times 4} = \frac{33 - 32}{60} = \frac{1}{60}](https://tex.z-dn.net/?f=+%5Cfrac%7B11%7D%7B20%7D+-+%5Cfrac%7B8%7D%7B15%7D+%3D+%5Cfrac%7B11+%5Ctimes+3%7D%7B20+%5Ctimes+3%7D+-+%5Cfrac%7B8+%5Ctimes+4%7D%7B15+%5Ctimes+4%7D+%3D+%5Cfrac%7B33+-+32%7D%7B60%7D+%3D+%5Cfrac%7B1%7D%7B60%7D+)
в)
![\frac{8}{9} - ( \frac{11}{12} - \frac{5}{18} ) + \frac{1}{4} = \frac{8}{9} - ( \frac{11 \times 3}{12 \times 3} - \frac{5 \times 2}{18 \times 2} ) + \frac{1}{4} = \frac{8}{9} - ( \frac{33 - 10}{60} ) + \frac{1}{4} = \frac{8}{9} - \frac{23}{36} + \frac{1}{4} = ( \frac{8 \times 4}{9 \times 4} - \frac{23}{36} ) + \frac{1}{4} = \frac{32 - 23}{36} + \frac{1}{4} = \frac{9}{36} + \frac{1}{4} = \frac{1}{4} + \frac{1}{4} = \frac{1 + 1}{4} = \frac{2}{4} = \frac{1}{2} \frac{8}{9} - ( \frac{11}{12} - \frac{5}{18} ) + \frac{1}{4} = \frac{8}{9} - ( \frac{11 \times 3}{12 \times 3} - \frac{5 \times 2}{18 \times 2} ) + \frac{1}{4} = \frac{8}{9} - ( \frac{33 - 10}{60} ) + \frac{1}{4} = \frac{8}{9} - \frac{23}{36} + \frac{1}{4} = ( \frac{8 \times 4}{9 \times 4} - \frac{23}{36} ) + \frac{1}{4} = \frac{32 - 23}{36} + \frac{1}{4} = \frac{9}{36} + \frac{1}{4} = \frac{1}{4} + \frac{1}{4} = \frac{1 + 1}{4} = \frac{2}{4} = \frac{1}{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B8%7D%7B9%7D+-+%28+%5Cfrac%7B11%7D%7B12%7D+-+%5Cfrac%7B5%7D%7B18%7D+%29+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B8%7D%7B9%7D+-+%28+%5Cfrac%7B11+%5Ctimes+3%7D%7B12+%5Ctimes+3%7D+-+%5Cfrac%7B5+%5Ctimes+2%7D%7B18+%5Ctimes+2%7D+%29+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B8%7D%7B9%7D+-+%28+%5Cfrac%7B33+-+10%7D%7B60%7D+%29+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B8%7D%7B9%7D+-+%5Cfrac%7B23%7D%7B36%7D+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%28+%5Cfrac%7B8+%5Ctimes+4%7D%7B9+%5Ctimes+4%7D+-+%5Cfrac%7B23%7D%7B36%7D+%29+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B32+-+23%7D%7B36%7D+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B9%7D%7B36%7D+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B1%7D%7B4%7D+%2B+%5Cfrac%7B1%7D%7B4%7D+%3D+%5Cfrac%7B1+%2B+1%7D%7B4%7D+%3D+%5Cfrac%7B2%7D%7B4%7D+%3D+%5Cfrac%7B1%7D%7B2%7D+)
2.
![(x + \frac{5}{8} ) - \frac{3}{4} = \frac{5}{12} - \frac{3}{8} \\ x + \frac{5}{8} - \frac{3}{4} = \frac{5}{12} - \frac{3}{8} \\ x + \frac{5 - 3 \times 2}{8} = \frac{5 \times 2}{12 \times 2} - \frac{3 \times 3}{8 \times 3} \\ x - \frac{1}{8} = \frac{1}{24} \\ x = \frac{1}{24} + \frac{1}{8} \\ x = \frac{1 + 1 \times 3}{24} = \frac{4}{24} = \frac{1}{6} \\ x = \frac{1}{6} (x + \frac{5}{8} ) - \frac{3}{4} = \frac{5}{12} - \frac{3}{8} \\ x + \frac{5}{8} - \frac{3}{4} = \frac{5}{12} - \frac{3}{8} \\ x + \frac{5 - 3 \times 2}{8} = \frac{5 \times 2}{12 \times 2} - \frac{3 \times 3}{8 \times 3} \\ x - \frac{1}{8} = \frac{1}{24} \\ x = \frac{1}{24} + \frac{1}{8} \\ x = \frac{1 + 1 \times 3}{24} = \frac{4}{24} = \frac{1}{6} \\ x = \frac{1}{6}](https://tex.z-dn.net/?f=%28x+%2B+%5Cfrac%7B5%7D%7B8%7D+%29+-+%5Cfrac%7B3%7D%7B4%7D+%3D+%5Cfrac%7B5%7D%7B12%7D+-+%5Cfrac%7B3%7D%7B8%7D+%5C%5C+x+%2B+%5Cfrac%7B5%7D%7B8%7D+-+%5Cfrac%7B3%7D%7B4%7D+%3D+%5Cfrac%7B5%7D%7B12%7D+-+%5Cfrac%7B3%7D%7B8%7D+%5C%5C+x+%2B+%5Cfrac%7B5+-+3+%5Ctimes+2%7D%7B8%7D+%3D+%5Cfrac%7B5+%5Ctimes+2%7D%7B12+%5Ctimes+2%7D+-+%5Cfrac%7B3+%5Ctimes+3%7D%7B8+%5Ctimes+3%7D+%5C%5C+x+-+%5Cfrac%7B1%7D%7B8%7D+%3D+%5Cfrac%7B1%7D%7B24%7D+%5C%5C+x+%3D+%5Cfrac%7B1%7D%7B24%7D+%2B+%5Cfrac%7B1%7D%7B8%7D+%5C%5C+x+%3D+%5Cfrac%7B1+%2B+1+%5Ctimes+3%7D%7B24%7D+%3D+%5Cfrac%7B4%7D%7B24%7D+%3D+%5Cfrac%7B1%7D%7B6%7D+%5C%5C+x+%3D+%5Cfrac%7B1%7D%7B6%7D+)
Ответ:
![x = \frac{1}{6} x = \frac{1}{6}](https://tex.z-dn.net/?f=x+%3D+%5Cfrac%7B1%7D%7B6%7D+)
3. а)
![\frac{11}{17} + \frac{1}{6} + \frac{6}{17} = \frac{11 \times 6}{17 \times 6} + \frac{1 \times 17}{6 \times 17} + \frac{6 \times 6}{17 \times 6} = \frac{66 + 17 + 36}{102} = \frac{119}{102} = \frac{119 \div 17}{102 \div 17} = \frac{7}{6} = 1 \frac{1}{6} \frac{11}{17} + \frac{1}{6} + \frac{6}{17} = \frac{11 \times 6}{17 \times 6} + \frac{1 \times 17}{6 \times 17} + \frac{6 \times 6}{17 \times 6} = \frac{66 + 17 + 36}{102} = \frac{119}{102} = \frac{119 \div 17}{102 \div 17} = \frac{7}{6} = 1 \frac{1}{6}](https://tex.z-dn.net/?f=+%5Cfrac%7B11%7D%7B17%7D+%2B+%5Cfrac%7B1%7D%7B6%7D+%2B+%5Cfrac%7B6%7D%7B17%7D+%3D+%5Cfrac%7B11+%5Ctimes+6%7D%7B17+%5Ctimes+6%7D+%2B+%5Cfrac%7B1+%5Ctimes+17%7D%7B6+%5Ctimes+17%7D+%2B+%5Cfrac%7B6+%5Ctimes+6%7D%7B17+%5Ctimes+6%7D+%3D+%5Cfrac%7B66+%2B+17+%2B+36%7D%7B102%7D+%3D+%5Cfrac%7B119%7D%7B102%7D+%3D+%5Cfrac%7B119+%5Cdiv+17%7D%7B102+%5Cdiv+17%7D+%3D+%5Cfrac%7B7%7D%7B6%7D+%3D+1+%5Cfrac%7B1%7D%7B6%7D+)
б)
![( \frac{4}{5} + \frac{13}{25} ) - \frac{8}{25} = \frac{4 \times 5}{5 \times 5} + \frac{13}{25} - \frac{8}{25} = \frac{20 + 13 - 8}{25} = \frac{25}{25} = 1 ( \frac{4}{5} + \frac{13}{25} ) - \frac{8}{25} = \frac{4 \times 5}{5 \times 5} + \frac{13}{25} - \frac{8}{25} = \frac{20 + 13 - 8}{25} = \frac{25}{25} = 1](https://tex.z-dn.net/?f=%28+%5Cfrac%7B4%7D%7B5%7D+%2B+%5Cfrac%7B13%7D%7B25%7D+%29+-+%5Cfrac%7B8%7D%7B25%7D+%3D+%5Cfrac%7B4+%5Ctimes+5%7D%7B5+%5Ctimes+5%7D+%2B+%5Cfrac%7B13%7D%7B25%7D+-+%5Cfrac%7B8%7D%7B25%7D+%3D+%5Cfrac%7B20+%2B+13+-+8%7D%7B25%7D+%3D+%5Cfrac%7B25%7D%7B25%7D+%3D+1)
в)
![\frac{9}{32} - ( \frac{1}{4} + \frac{1}{32} ) = \frac{9}{32} - \frac{1 \times 8}{4 \times 8} - \frac{1}{32} = \frac{9 - 8 - 1}{32} = 0 \frac{9}{32} - ( \frac{1}{4} + \frac{1}{32} ) = \frac{9}{32} - \frac{1 \times 8}{4 \times 8} - \frac{1}{32} = \frac{9 - 8 - 1}{32} = 0](https://tex.z-dn.net/?f=+%5Cfrac%7B9%7D%7B32%7D+-+%28+%5Cfrac%7B1%7D%7B4%7D+%2B+%5Cfrac%7B1%7D%7B32%7D+%29+%3D+%5Cfrac%7B9%7D%7B32%7D+-+%5Cfrac%7B1+%5Ctimes+8%7D%7B4+%5Ctimes+8%7D+-+%5Cfrac%7B1%7D%7B32%7D+%3D+%5Cfrac%7B9+-+8+-+1%7D%7B32%7D+%3D+0)
4. Труба наполнила водой 7/20 частей бассейна => весь бассейн - 20/20 частей.
![\frac{20}{20} - \frac{7}{20} = \frac{13}{20} \frac{20}{20} - \frac{7}{20} = \frac{13}{20}](https://tex.z-dn.net/?f=+%5Cfrac%7B20%7D%7B20%7D+-+%5Cfrac%7B7%7D%7B20%7D+%3D+%5Cfrac%7B13%7D%7B20%7D+)
13/20 частей бассейна осталось заполнить водой.
![\frac{7}{20} < \frac{13}{20} \frac{7}{20} < \frac{13}{20}](https://tex.z-dn.net/?f=+%5Cfrac%7B7%7D%7B20%7D+%26lt%3B+%5Cfrac%7B13%7D%7B20%7D+)
13/20(часть, которую осталось заполнить водой) > 7/20(заполненная водой часть бассейна) на 5/20.
5.
![\frac{3t + 1}{35} = \frac{2}{7} \\ (3t + 1) \times 7 = 70 \\ 3t + 1 = 10 \\ 3t = 10 - 1 \\ 3t = 9 \\ t = 3 \frac{3t + 1}{35} = \frac{2}{7} \\ (3t + 1) \times 7 = 70 \\ 3t + 1 = 10 \\ 3t = 10 - 1 \\ 3t = 9 \\ t = 3](https://tex.z-dn.net/?f=+%5Cfrac%7B3t+%2B+1%7D%7B35%7D+%3D+%5Cfrac%7B2%7D%7B7%7D+%5C%5C+%283t+%2B+1%29+%5Ctimes+7+%3D+70+%5C%5C+3t+%2B+1+%3D+10+%5C%5C+3t+%3D+10+-+1+%5C%5C+3t+%3D+9+%5C%5C+t+%3D+3)
Ответ: t = 3
I вариант.
1. а)
![\frac{5}{9} + \frac{7}{8} = \frac{5 \times 8}{9 \times 8} + \frac{7 \times 9}{8 \times 9} = \frac{40 + 63}{72} = \frac{103}{72} = 1 \frac{31}{72} \frac{5}{9} + \frac{7}{8} = \frac{5 \times 8}{9 \times 8} + \frac{7 \times 9}{8 \times 9} = \frac{40 + 63}{72} = \frac{103}{72} = 1 \frac{31}{72}](https://tex.z-dn.net/?f=+%5Cfrac%7B5%7D%7B9%7D+%2B+%5Cfrac%7B7%7D%7B8%7D+%3D+%5Cfrac%7B5+%5Ctimes+8%7D%7B9+%5Ctimes+8%7D+%2B+%5Cfrac%7B7+%5Ctimes+9%7D%7B8+%5Ctimes+9%7D+%3D+%5Cfrac%7B40+%2B+63%7D%7B72%7D+%3D+%5Cfrac%7B103%7D%7B72%7D+%3D+1+%5Cfrac%7B31%7D%7B72%7D+)
б)
![\frac{9}{20} - \frac{5}{12} = \frac{9 \times 3}{20 \times 3} - \frac{5 \times 5}{12 \times 5} = \frac{27 - 25}{60} = \frac{2}{60} = \frac{1}{30} \frac{9}{20} - \frac{5}{12} = \frac{9 \times 3}{20 \times 3} - \frac{5 \times 5}{12 \times 5} = \frac{27 - 25}{60} = \frac{2}{60} = \frac{1}{30}](https://tex.z-dn.net/?f=+%5Cfrac%7B9%7D%7B20%7D+-+%5Cfrac%7B5%7D%7B12%7D+%3D+%5Cfrac%7B9+%5Ctimes+3%7D%7B20+%5Ctimes+3%7D+-+%5Cfrac%7B5+%5Ctimes+5%7D%7B12+%5Ctimes+5%7D+%3D+%5Cfrac%7B27+-+25%7D%7B60%7D+%3D+%5Cfrac%7B2%7D%7B60%7D+%3D+%5Cfrac%7B1%7D%7B30%7D+)
в)
![\frac{9}{10} - ( \frac{3}{5} + \frac{1}{6} ) + \frac{2}{3} = \frac{9}{10} - ( \frac{3 \times 6}{5 \times 6} + \frac{1 \times 5}{6 \times 5} ) + \frac{2}{3} = \frac{9}{10} - \frac{18 + 5}{30} + \frac{2}{3} = \frac{9 \times 3}{10 \times 3} - \frac{23}{30} + \frac{2 \times 10}{3 \times 10} = \frac{27 - 23 + 20}{30} = \frac{24}{30} = \frac{4}{5} = 0.8 \frac{9}{10} - ( \frac{3}{5} + \frac{1}{6} ) + \frac{2}{3} = \frac{9}{10} - ( \frac{3 \times 6}{5 \times 6} + \frac{1 \times 5}{6 \times 5} ) + \frac{2}{3} = \frac{9}{10} - \frac{18 + 5}{30} + \frac{2}{3} = \frac{9 \times 3}{10 \times 3} - \frac{23}{30} + \frac{2 \times 10}{3 \times 10} = \frac{27 - 23 + 20}{30} = \frac{24}{30} = \frac{4}{5} = 0.8](https://tex.z-dn.net/?f=+%5Cfrac%7B9%7D%7B10%7D+-+%28+%5Cfrac%7B3%7D%7B5%7D+%2B+%5Cfrac%7B1%7D%7B6%7D+%29+%2B+%5Cfrac%7B2%7D%7B3%7D+%3D+%5Cfrac%7B9%7D%7B10%7D+-+%28+%5Cfrac%7B3+%5Ctimes+6%7D%7B5+%5Ctimes+6%7D+%2B+%5Cfrac%7B1+%5Ctimes+5%7D%7B6+%5Ctimes+5%7D+%29+%2B+%5Cfrac%7B2%7D%7B3%7D+%3D+%5Cfrac%7B9%7D%7B10%7D+-+%5Cfrac%7B18+%2B+5%7D%7B30%7D+%2B+%5Cfrac%7B2%7D%7B3%7D+%3D+%5Cfrac%7B9+%5Ctimes+3%7D%7B10+%5Ctimes+3%7D+-+%5Cfrac%7B23%7D%7B30%7D+%2B+%5Cfrac%7B2+%5Ctimes+10%7D%7B3+%5Ctimes+10%7D+%3D+%5Cfrac%7B27+-+23+%2B+20%7D%7B30%7D+%3D+%5Cfrac%7B24%7D%7B30%7D+%3D+%5Cfrac%7B4%7D%7B5%7D+%3D+0.8)
2.
![(x - \frac{4}{5} ) + \frac{1}{30} = \frac{1}{6} - \frac{1}{10} \\ x - \frac{4}{5} + \frac{1}{30} = \frac{1 \times 5}{6 \times 5} - \frac{1 \times 3}{10 \times 3} \\ x - \frac{4}{5} + \frac{1}{30} = \frac{2}{30} \\ x - \frac{4 \times 6}{5 \times 6} + \frac{1}{30} = \frac{2}{30} \\ x - \frac{23}{30} = \frac{2}{30} \\ x = \frac{2}{30} + \frac{23}{30} \\ x = \frac{25}{30} = \frac{5}{6} \\ x = \frac{5}{6} (x - \frac{4}{5} ) + \frac{1}{30} = \frac{1}{6} - \frac{1}{10} \\ x - \frac{4}{5} + \frac{1}{30} = \frac{1 \times 5}{6 \times 5} - \frac{1 \times 3}{10 \times 3} \\ x - \frac{4}{5} + \frac{1}{30} = \frac{2}{30} \\ x - \frac{4 \times 6}{5 \times 6} + \frac{1}{30} = \frac{2}{30} \\ x - \frac{23}{30} = \frac{2}{30} \\ x = \frac{2}{30} + \frac{23}{30} \\ x = \frac{25}{30} = \frac{5}{6} \\ x = \frac{5}{6}](https://tex.z-dn.net/?f=%28x+-+%5Cfrac%7B4%7D%7B5%7D+%29+%2B+%5Cfrac%7B1%7D%7B30%7D+%3D+%5Cfrac%7B1%7D%7B6%7D+-+%5Cfrac%7B1%7D%7B10%7D+%5C%5C+x+-+%5Cfrac%7B4%7D%7B5%7D+%2B+%5Cfrac%7B1%7D%7B30%7D+%3D+%5Cfrac%7B1+%5Ctimes+5%7D%7B6+%5Ctimes+5%7D+-+%5Cfrac%7B1+%5Ctimes+3%7D%7B10+%5Ctimes+3%7D+%5C%5C+x+-+%5Cfrac%7B4%7D%7B5%7D+%2B+%5Cfrac%7B1%7D%7B30%7D+%3D+%5Cfrac%7B2%7D%7B30%7D+%5C%5C+x+-+%5Cfrac%7B4+%5Ctimes+6%7D%7B5+%5Ctimes+6%7D+%2B+%5Cfrac%7B1%7D%7B30%7D+%3D+%5Cfrac%7B2%7D%7B30%7D+%5C%5C+x+-+%5Cfrac%7B23%7D%7B30%7D+%3D+%5Cfrac%7B2%7D%7B30%7D+%5C%5C+x+%3D+%5Cfrac%7B2%7D%7B30%7D+%2B+%5Cfrac%7B23%7D%7B30%7D+%5C%5C+x+%3D+%5Cfrac%7B25%7D%7B30%7D+%3D+%5Cfrac%7B5%7D%7B6%7D+%5C%5C+x+%3D+%5Cfrac%7B5%7D%7B6%7D+)
Ответ:
![x = \frac{5}{6} x = \frac{5}{6}](https://tex.z-dn.net/?f=x+%3D+%5Cfrac%7B5%7D%7B6%7D+)
3. а)
![\frac{19}{21} + \frac{1}{5} + \frac{2}{21} = \frac{19 \times 5}{21 \times 5} + \frac{1 \times 21}{5 \times 21} + \frac{2 \times 5}{21 \times 5} = \frac{95 + 21 + 10}{105} = \frac{126}{105} = \frac{6}{5} = 1 \frac{1}{5} = 1.2 \frac{19}{21} + \frac{1}{5} + \frac{2}{21} = \frac{19 \times 5}{21 \times 5} + \frac{1 \times 21}{5 \times 21} + \frac{2 \times 5}{21 \times 5} = \frac{95 + 21 + 10}{105} = \frac{126}{105} = \frac{6}{5} = 1 \frac{1}{5} = 1.2](https://tex.z-dn.net/?f=+%5Cfrac%7B19%7D%7B21%7D+%2B+%5Cfrac%7B1%7D%7B5%7D+%2B+%5Cfrac%7B2%7D%7B21%7D+%3D+%5Cfrac%7B19+%5Ctimes+5%7D%7B21+%5Ctimes+5%7D+%2B+%5Cfrac%7B1+%5Ctimes+21%7D%7B5+%5Ctimes+21%7D+%2B+%5Cfrac%7B2+%5Ctimes+5%7D%7B21+%5Ctimes+5%7D+%3D+%5Cfrac%7B95+%2B+21+%2B+10%7D%7B105%7D+%3D+%5Cfrac%7B126%7D%7B105%7D+%3D+%5Cfrac%7B6%7D%7B5%7D+%3D+1+%5Cfrac%7B1%7D%7B5%7D+%3D+1.2)
б)
![\frac{17}{36} - ( \frac{5}{36} + \frac{1}{3} ) = \frac{17}{36} - \frac{5 + 1 \times 12}{36} = \frac{17}{36} - \frac{17}{36} = 0 \frac{17}{36} - ( \frac{5}{36} + \frac{1}{3} ) = \frac{17}{36} - \frac{5 + 1 \times 12}{36} = \frac{17}{36} - \frac{17}{36} = 0](https://tex.z-dn.net/?f=+%5Cfrac%7B17%7D%7B36%7D+-+%28+%5Cfrac%7B5%7D%7B36%7D+%2B+%5Cfrac%7B1%7D%7B3%7D+%29+%3D+%5Cfrac%7B17%7D%7B36%7D+-+%5Cfrac%7B5+%2B+1+%5Ctimes+12%7D%7B36%7D+%3D+%5Cfrac%7B17%7D%7B36%7D+-+%5Cfrac%7B17%7D%7B36%7D+%3D+0)
в)
![( \frac{2}{3} + \frac{7}{15} ) - \frac{2}{15} = \frac{2 \times 5 + 7}{15} - \frac{2}{15} = \frac{17}{15} - \frac{2}{15} = \frac{15}{15} = 1 ( \frac{2}{3} + \frac{7}{15} ) - \frac{2}{15} = \frac{2 \times 5 + 7}{15} - \frac{2}{15} = \frac{17}{15} - \frac{2}{15} = \frac{15}{15} = 1](https://tex.z-dn.net/?f=%28+%5Cfrac%7B2%7D%7B3%7D+%2B+%5Cfrac%7B7%7D%7B15%7D+%29+-+%5Cfrac%7B2%7D%7B15%7D+%3D+%5Cfrac%7B2+%5Ctimes+5+%2B+7%7D%7B15%7D+-+%5Cfrac%7B2%7D%7B15%7D+%3D+%5Cfrac%7B17%7D%7B15%7D+-+%5Cfrac%7B2%7D%7B15%7D+%3D+%5Cfrac%7B15%7D%7B15%7D+%3D+1)
4. Велосипедист проехал 9/20 частей всего пути => весь путь - 20/20 частей.
![\frac{20}{20} - \frac{9}{20} = \frac{11}{20} \frac{20}{20} - \frac{9}{20} = \frac{11}{20}](https://tex.z-dn.net/?f=+%5Cfrac%7B20%7D%7B20%7D+-+%5Cfrac%7B9%7D%7B20%7D+%3D+%5Cfrac%7B11%7D%7B20%7D+)
11/20 частей от всего пути осталось проехать велосипедисту.
![\frac{9}{20} < \frac{11}{20} \frac{9}{20} < \frac{11}{20}](https://tex.z-dn.net/?f=+%5Cfrac%7B9%7D%7B20%7D+%26lt%3B+%5Cfrac%7B11%7D%7B20%7D+)
9/20(часть, которую проехал велосипедист) < 11/20(часть, которую осталось проехать) на 3/20.
5.
![\frac{2x - 1}{15} = \frac{3}{5} \\ (2x - 1) \times 5 = 45 \\ 2x - 1 = 9 \\ 2x = 9 + 1 \\ 2x = 10 \\ x = 10 \div 2 \\ x = 5 \frac{2x - 1}{15} = \frac{3}{5} \\ (2x - 1) \times 5 = 45 \\ 2x - 1 = 9 \\ 2x = 9 + 1 \\ 2x = 10 \\ x = 10 \div 2 \\ x = 5](https://tex.z-dn.net/?f=+%5Cfrac%7B2x+-+1%7D%7B15%7D+%3D+%5Cfrac%7B3%7D%7B5%7D+%5C%5C+%282x+-+1%29+%5Ctimes+5+%3D+45+%5C%5C+2x+-+1+%3D+9+%5C%5C+2x+%3D+9+%2B+1+%5C%5C+2x+%3D+10+%5C%5C+x+%3D+10+%5Cdiv+2+%5C%5C+x+%3D+5)
Ответ: х = 5
1. а)
б)
в)
2.
Ответ:
3. а)
б)
в)
4. Труба наполнила водой 7/20 частей бассейна => весь бассейн - 20/20 частей.
13/20 частей бассейна осталось заполнить водой.
13/20(часть, которую осталось заполнить водой) > 7/20(заполненная водой часть бассейна) на 5/20.
5.
Ответ: t = 3
I вариант.
1. а)
б)
в)
2.
Ответ:
3. а)
б)
в)
4. Велосипедист проехал 9/20 частей всего пути => весь путь - 20/20 частей.
11/20 частей от всего пути осталось проехать велосипедисту.
9/20(часть, которую проехал велосипедист) < 11/20(часть, которую осталось проехать) на 3/20.
5.
Ответ: х = 5
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