Question

1) х + 3,2 при х = -3,2 2)-5х при х = -2 8/15 3)12х - 7 при х = 0,05 4)3-1,5х при х = - 1/3 5)2х-у/х-3у при х = -1,у = 1/3

Answer 1

$1)x + 3.2 = - 3.2 + 3.2 = 0 \\ 2) - 5x = - 5 \times ( - 2 \frac{8}{15} ) = - 5 \times ( - \frac{38}{15} ) = 5 \times \frac{38}{15} = \frac{38}{3} = 12 \frac{2}{3} \\ 3)12x - 7 = 12 \times 0.05 - 7 = 0.6 - 7 = - 6.4 \\ 4)3 - 1.5x = 3 - 1.5 \times ( - \frac{1}{3} ) = 3 - \frac{3}{2} \times ( - \frac{1}{3} ) = 3 + \frac{1}{2} = 3.5 \\5) 2x - \frac{y}{x} - 3y \\ x = \frac{1}{3} . \: \: \: y = - 1 \times \frac{1}{3} = - \frac{1}{3} \\ 2 \times \frac{1}{3} - \frac{ - \frac{1}{3} }{ \frac{1}{3} } - 3 \times ( - \frac{1}{3} ) = \frac{2}{3} - ( - 1) - ( - 1) = \frac{2}{3} + 1 + 1 = 2 \frac{2}{3}$