Question

Найдите решение систем уравнений способом подстановки​

Answer 1

$1) - y + 0.5 + 2y = 0.3 \ y + 0.5 = 0.3 \ y = 0.3 - 0.5 \ y = - 0.2 \ \ x = - y + 0.5 = - ( - 0.2) + 0.5 = 0.2 + 0.5 = 0.7$

$- x - 6. 9- 8x = 83.1 \ - 9x = 83.1 + 6.9 \ - 9x = 90 \ x = 90 div ( - 9) \ x = - 10 \ y = - x - 6.9 = - ( - 10) - 6.9 = 10 - 6.9 = 3.1$

$21x + 0.9 - x = - 15.1 \ 20x = - 15.1 - 0.9 \ 20x = - 16 \ x = frac{ - 16}{ - 20} \ x = frac{4}{5} \ x = 0.8 \ \ y = 0.9 - x = 0.9 - 0.8 = 0.1$