Question

Найти значение выражения -5x при x=-2целых8/15;
3-1.5x при x=-1/3;
2x-y/x-3y при x=-1, y=1/3

Answer 1

$- 5x$

$x = - 2 \frac{8}{15}$

$- 5 \times ( - 2 \frac{8}{15} ) = - 5 \times ( - \frac{38}{15} ) = \frac{38}{3} = 12 \frac{2}{3}$

$3 - 1.5x$

$x = - \frac{1}{3}$

$3 - 1.5 \times ( - \frac{1}{3} ) = 3 + \frac{15}{10} \times \frac{1}{3} = \frac{5}{10} = 0.5$

$2x - \frac{y}{x} - 3y$

$x = - 1$

$y = \frac{1}{3}$

$- 2 - \frac{ \frac{1}{3} }{ - 1} - 3 \times \frac{1}{3} = - 2 + \frac{1}{3} - 1 = - 2 \frac{2}{3}$