Question

6x+9y= -15
-2x+y= -15

Answer 1

`x=5 \quad and \quad y=-5.`

Explanation:

`\left\{\begin{matrix} 6x+9y=-15& \\ -2x+y=-15 & \end{matrix}\right.\\\\\Rightarrow \left\{\begin{matrix} 2x+3y=-5& (1)\\ -2x+y=-15& (2)\end{matrix}\right.\\(1)+(2) \Rightarrow 4y=-20\Rightarrow y=-20:4=-5\\From \quad (2) \Rightarrow x=(-15-y):(-2)=(-15-(-5)):(-2)=(-10):(-2)=5\\Therefore,\\x=5 \quad and \quad y=-5.`