Задание 4. Найдите значение выражения: 1) 10·(1/5)²−12·1/5; 2) 8·(1/4)²−14·1/4; 3) 21·(1/7)²−10·1/7; 4) 6·(1/3)²−17·1/3; 5) 18·(1/9)²−20·1/9; 6) 15·(1/5)²−8·1/5.

Question

Accepted Answer

\(10\cdot\frac{1}{25}-12\cdot\frac{1}{5}=\frac{2}{5}-\frac{12}{5}=-2\).
\(8\cdot\frac{1}{16}-14\cdot\frac{1}{4}=\frac{1}{2}-\frac{7}{2}=-3\).
\(21\cdot\frac{1}{49}-10\cdot\frac{1}{7}=\frac{3}{7}-\frac{10}{7}=-1\).
\(6\cdot\frac{1}{9}-17\cdot\frac{1}{3}=\frac{2}{3}-\frac{17}{3}=-5\).
\(18\cdot\frac{1}{81}-20\cdot\frac{1}{9}=\frac{2}{9}-\frac{20}{9}=-2\).
\(15\cdot\frac{1}{25}-8\cdot\frac{1}{5}=\frac{3}{5}-\frac{8}{5}=-1\).

Ответ: 1) −2; 2) −3; 3) −1; 4) −5; 5) −2; 6) −1.