Question

{9x+8y=-2.            Найдите решение системы уравнений

{4X+5y=-11

Answer 1

 

$<var>9x + 8y = -2\\ 4x+5y = -11\\\\ 4x = -5y-11\\\\ x =\frac{-5y-11}{4}\\\\ 9(\frac{-5y-11}{4}) + 8y = -2 \ |*4\\\\ -45y-99+32y = -8\\\\ -13y = -8+99 = 91\\\\ y = -\frac{91}{13}\\\\ y = -7\\\\ 4x = -5(-7)-11 = 35-11 = 24\\\\ x = \frac{24}{4} = 6\\\\ \fbox{x = 6, y = -7}</var>$