Упр.622 Часть 2 ГДЗ Виленкин Жохов 6 класс (Математика)

Задача

а) -6 * (1/6 — 1/3 y) — 2 * (1 — 3 1/2 y);
б) -8 * (1/8 — 1/4 y) — 3 * (1 — 2 1/3 y).

Подробный ответ

При $$y=-2\frac{3}{5}=-\frac{13}{5}$$ упростим выражения.

а)

$$ -6\left(\frac{1}{6}-\frac{1}{3}y\right)-2\left(1-3\frac{1}{2}y\right) $$
$$ =-1+2y-2\left(1-\frac{7}{2}y\right) $$
$$ =-1+2y-2+7y $$
$$ =9y-3 $$
Подставим $$y=-\frac{13}{5}$$:
$$ 9\cdot\left(-\frac{13}{5}\right)-3=-\frac{117}{5}-3=-\frac{117}{5}-\frac{15}{5}=-\frac{132}{5}=-26\frac{2}{5}=-26{,}4. $$

б)

$$ -8\left(\frac{1}{8}-\frac{1}{4}y\right)-3\left(1-2\frac{1}{3}y\right) $$
$$ =-1+2y-3\left(1-\frac{7}{3}y\right) $$
$$ =-1+2y-3+7y $$
$$ =9y-4 $$
Подставим $$y=-\frac{13}{5}$$:
$$ 9\cdot\left(-\frac{13}{5}\right)-4=-\frac{117}{5}-4=-\frac{117}{5}-\frac{20}{5}=-\frac{137}{5}=-27\frac{2}{5}=-27{,}4. $$