Question

помогите 7 клас пожалуйста алгебра

Answer 1

1) 11^3 = 121*11 = 1331
2) 37^2 = 1369
3) 370^2 = (37*10)^2 = 1369 * 10^2 = 136900
4) 1100^3 = (11*100)^3 =11^3 * 10^6 = 1331 * 10^6
5) (-5)^3 = -125
6) (-13)^2 = 169
7) (-0.5)^3 = (-5/10)^3 = -125/1000 = -0,125
8) (-0,13)^2 = (-13/100)^2= 169/10000 = 0,0169
9) (4/9)^2=4^2/9^2 = 16/81
10) (-3/7)^3 = - 3^3/7^3 = -27/343
11) (-1 1/5)^2 = (-6/5)^2 = 36/25
12) (1 1/5)^3 = (6/5)^3 = 6^3/5^3 = 216/125

1) 7+5,31+9+13,49 = 12,31 + 9,0 + 13,49 = 25,8 + 9,0 = 34,8
2)62,7 +8,31+5,79+0,07 = 62,7 + 14,1+0,07 = 81,8+0,07 = 81,87
3) 8,31 - (4,29+3,721) = 8,31 - 8,011 = 0,299
4) (8,21+9,73)-0,001 = 17,94 - 0,001 = 17,939
5)
$3 \div 1 \frac{1}{2} + 5 \div 1\frac{1}{4} = 3 \div \frac{3}{2} + 5 \div \frac{5}{4} = 3 \times \frac{2}{3} + 5 \times \frac{4}{5} = 2 + 4 = 6$
6)
$10 \frac{2}{3} - 5 \frac{1}{3} \div 3 \frac{1}{5} = \frac{32}{ 3} - \frac{16}{3} \div \frac{16}{5} = \frac{32}{3} - \frac{16}{3} \times \frac{5}{16} = \frac{32}{3} - \frac{5}{3} = \frac{27}{3} = 9$
7)
$(10 \frac{2}{3} - 5 \frac{1}{3} ) \div 3 \frac{1}{3} = ( \frac{32}{3} - \frac{16}{3} ) \div \frac{10}{3} = \frac{16}{3} \times \frac{3}{10} = \frac{16}{10} = 1.6$
8)
$4 \frac{1}{2} \times \frac{8}{9} - 5 \frac{1}{3} \div 10 \frac{2}{3} = \frac{9}{2} \times \frac{8}{9} - \frac{16}{3} \div \frac{32}{3} = 4 - \frac{16}{3} \times \frac{3}{32} = 4 - \frac{1}{2} = \frac{7}{2} = 3.5$
9)
0,7*1,3 +5,1:0,17 =
$\frac{7}{10} \times \frac{13}{10} + \frac{51}{10} \div \frac{17}{100} = \frac{91}{100} + \frac{51}{10} \times \frac{100}{17} = \frac{91}{100} + 30 = 30 + 0.91 = 30.91$
10) 3,38-2,24:1,25 =
$3 \frac{38}{100} - 2 \frac{24}{100} \div 1\frac{25}{100} = \frac{338}{100} - \frac{224}{100} \times \frac{100}{125} = \frac{338}{100} - \frac{224}{125} = \frac{338}{100} - \frac{1792}{1000} = 3.78 - 1.792 = 1.588$
11) (3,38-2,24):1,24 = 1,14:1,24 =
$\frac{114}{100} \div \frac{124}{100} = \frac{114}{100} \times \frac{100}{124} = \frac{114}{124} = \frac{57}{62}$
12) 31,7:63,4-23,4:11,7 =
$\frac{317}{10} \div \frac{634}{10} - \frac{234}{10} \div \frac{117}{10} = \frac{317}{10} \times \frac{10}{634} - \frac{234}{10} \times \frac{10}{117} = \frac{1}{2} - 2 = - \frac{3}{2} = - 1.5$
3.1. ) 100% - 200
25% - x
x= 25*200/100 = 50

2) 100 - 3
25% - x
x=25*3/100= 3/4

3)100% - 5,7
25% - x
x=25*5,7/100=5,7/4 = 57/40 = 1 целая 17/70

4) 100% - 0,08
25% - x
x=25*0,08/100 = 0,08/4 = 0,02

3.2.
1) 17% - 340
100% - x
x=100*340/17 = 2000

2) 17% - 8,5
100% - x
x=100*8,5/17 = 50

3) 17% - 0,051
100% - x
x=100*0,051/17 = 0,3

4)17% - 2,89
100% - x
x=100*2,89/17 = 17

3.3. 43%=0,43
75%=0,75
25%=0,25
60%=0,6
11,4%=0,114

3.4. 0,5 = 50%
0,37=37%
0,7=70%
1,35=135%
1,2=120%