Выполнить вычисления: 1) $\left(\frac{7}{10}-\frac{4}{10}\right)^2$; 2) $\left(\frac{6}{7}-\frac{3}{7}\right)^2$; 3) $\left(\frac{2}{9}+\frac{5}{9}\right)^2$; 4) $\left(\frac{4}{5}-\frac{2}{5}\right)^2$; 5) $\left(\frac{4}{5}\right)^2-\left(\frac{2}{5}\right)^2$; 6) $\left(\frac{2}{7}+\frac{4}{7}\right)\cdot\frac{7}{12}$; 7) $\frac{8}{15}\cdot\left(\frac{3}{8}+\frac{3}{8}\right)$; 8) $\left(\frac{7}{10}-\frac{4}{10}\right)\cdot\frac{20}{21}$; 9) $\frac{9}{14}\cdot\left(\frac{7}{15}+\frac{4}{15}\right)$; 10) $\frac{21}{80}\cdot\left(\frac{33}{35}-\frac{13}{35}\right)$; 11) $\frac{5}{6}\cdot\frac{4}{15}\cdot9$, затем $\frac{12}{?}\cdot\frac{9}{?}$; 12) $6\frac{1}{18}-15$; 13) $\frac{7}{12}\cdot20\cdot\frac{3}{35}$; 14) $\frac{9}{28}\cdot\frac{7}{45}\cdot10$; 15) $\frac{9}{26}\cdot\frac{13}{12}\cdot28$.

Question

Вопрос: $Фото задания: Выполнить вычисления: 1) $\left(\frac{7}{10}-\frac{4}{10}\right)^2$; 2) $\left(\frac{6}{7}-\frac{3}{7}\right)^2$; 3)…$ Фото задания

Выполнить вычисления: 1) $\left(\frac{7}{10}-\frac{4}{10}\right)^2$; 2) $\left(\frac{6}{7}-\frac{3}{7}\right)^2$; 3) $\left(\frac{2}{9}+\frac{5}{9}\right)^2$; 4) $\left(\frac{4}{5}-\frac{2}{5}\right)^2$; 5) $\left(\frac{4}{5}\right)^2-\left(\frac{2}{5}\right)^2$; 6) $\left(\frac{2}{7}+\frac{4}{7}\right)\cdot\frac{7}{12}$; 7) $\frac{8}{15}\cdot\left(\frac{3}{8}+\frac{3}{8}\right)$; 8) $\left(\frac{7}{10}-\frac{4}{10}\right)\cdot\frac{20}{21}$; 9) $\frac{9}{14}\cdot\left(\frac{7}{15}+\frac{4}{15}\right)$; 10) $\frac{21}{80}\cdot\left(\frac{33}{35}-\frac{13}{35}\right)$; 11) $\frac{5}{6}\cdot\frac{4}{15}\cdot9$, затем $\frac{12}{?}\cdot\frac{9}{?}$; 12) $6\frac{1}{18}-15$; 13) $\frac{7}{12}\cdot20\cdot\frac{3}{35}$; 14) $\frac{9}{28}\cdot\frac{7}{45}\cdot10$; 15) $\frac{9}{26}\cdot\frac{13}{12}\cdot28$.

Accepted Answer

$\left(\frac{7}{10}-\frac{4}{10}\right)^2=\left(\frac{3}{10}\right)^2=\frac{9}{100}$.
$\left(\frac{6}{7}-\frac{3}{7}\right)^2=\left(\frac{3}{7}\right)^2=\frac{9}{49}$.
$\left(\frac{2}{9}+\frac{5}{9}\right)^2=\left(\frac{7}{9}\right)^2=\frac{49}{81}$.
$\left(\frac{4}{5}-\frac{2}{5}\right)^2=\left(\frac{2}{5}\right)^2=\frac{4}{25}$.
$\left(\frac{4}{5}\right)^2-\left(\frac{2}{5}\right)^2=\frac{16}{25}-\frac{4}{25}=\frac{12}{25}$.
$\left(\frac{2}{7}+\frac{4}{7}\right)\cdot\frac{7}{12}=\frac{6}{7}\cdot\frac{7}{12}=\frac12$.
$\frac{8}{15}\cdot\left(\frac38+\frac38\right)=\frac{8}{15}\cdot\frac34=\frac25$.
$\left(\frac{7}{10}-\frac{4}{10}\right)\cdot\frac{20}{21}=\frac3{10}\cdot\frac{20}{21}=\frac27$.
$\frac9{14}\cdot\left(\frac7{15}+\frac4{15}\right)=\frac9{14}\cdot\frac{11}{15}=\frac{33}{70}$.
$\frac{21}{80}\cdot\left(\frac{33}{35}-\frac{13}{35}\right)=\frac{21}{80}\cdot\frac47=\frac3{20}$.
$\frac56\cdot\frac4{15}\cdot9=2$. Второе выражение на фотографии неразборчиво.
$6\frac1{18}-15=\frac{109}{18}-\frac{270}{18}=-\frac{161}{18}=-8\frac{17}{18}$.
$\frac7{12}\cdot20\cdot\frac3{35}=1$.
$\frac9{28}\cdot\frac7{45}\cdot10=\frac5{14}$.
$\frac9{26}\cdot\frac{13}{12}\cdot28=\frac{63}{6}=10\frac12$.

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