Question

помогите пожалуйста
По действиям пожалуйста
пример под буквой (В)

Answer 1

$\displaystyle \tt 2). \ \ \frac{3,05^{2}-2,55^{2}}{0,35\cdot 388-28,8\cdot (20,56-14,501:0,85)}= \\\\\\=\frac{(3,05-2,55)(3,05+2,55)}{3,5\cdot 38,8-28,8\cdot(20,56-17,06)}=\\\\\\=\frac{0,5\cdot5,6}{3,5\cdot38,8-3,5\cdot28,8}=\frac{2,8}{3,5\cdot10}=\frac{4}{50}=0,08;$    

$\displaystyle \tt 3). \ \ \frac{\left(3\dfrac{9}{20}+1\dfrac{1}{6}\right):27,7+5\dfrac{1}{7}\cdot3,85-14\dfrac{3}{20}}{\left(1,75:\dfrac{2}{3}-1,75:1\dfrac{1}{8}\right):\dfrac{7}{12}}=\\\\\\=\frac{\dfrac{207+70}{60}\cdot\dfrac{10}{277}+\dfrac{36}{7}\cdot\dfrac{385}{100}-14,15}{1,75\cdot \left(\dfrac{3}{2}-\dfrac{8}{9}\right)\cdot\dfrac{12}{7}}=$

$\displaystyle \tt =\frac{\dfrac{1}{6}+19,8-14,15}{1,75\cdot \dfrac{11}{18}\cdot \dfrac{12}{7}}=\frac{\dfrac{1}{6}+5,65}{\dfrac{11}{6}}=\frac{1}{11}+\frac{565}{100}\cdot \frac{6}{11}=\frac{10}{110}+3\frac{9}{110}=3\frac{19}{110};$

По действиям:

$\displaystyle \tt 1). \ \ 3\frac{9}{20}+1\frac{1}{6}=\frac{69}{20}+\frac{7}{6}=\frac{207+70}{60}=\frac{277}{60};\\\\\\2). \ \ \frac{277}{60}:27,7 =\frac{277}{60}\cdot\frac{10}{277}=\frac{1}{6};\\\\\\3). \ \ 5\frac{1}{7}\cdot3,85=\frac{36}{7}\cdot\frac{385}{100}=19,8;\\\\\\4). \ \ 19,8-14\frac{3}{20}=19,8-14,15=5,65\\\\\\5). \ \ \frac{1}{6}+5,65=\frac{10}{60}+\frac{339}{60}=\frac{349}{60};$

$\displaystyle \tt 6). \ \ 1,75:\frac{2}{3}=\frac{7}{4}\cdot\frac{3}{2}=\frac{21}{8};\\\\\\7). \ \ 1,75:1\frac{1}{8}=\frac{7}{4}\cdot\frac{8}{9}=\frac{14}{9};\\\\\\8). \ \ \frac{21}{8}-\frac{14}{9}=\frac{189-112}{72}=\frac{77}{72};\\\\\\9). \ \ \frac{77}{72}:\frac{7}{12}=\frac{77}{72}\cdot\frac{12}{7}=\frac{11}{6};\\\\\\10). \ \ \frac{349}{60}:\frac{11}{6}=\frac{349}{60}\cdot\frac{6}{11}=\frac{349}{110}=3\frac{19}{110};$