Question

(4x-y=-15)
(3x-2y=-10)
​

Answer 1

x = -4 and y = -1 → (-4, -1)

Explanation:

`\left\{\begin{array}{ccc}4x-y=-15&\text{multiply both sides by (-2)}\\3x-2y=-10\end{array}\right\\\underline{+\left\{\begin{array}{ccc}-8x+2y=30\\3x-2y=-10\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad\qquad-5x=20\qquad\text{divide both sides by (-5)}\\.\qquad\qquad\boxed{x=-4}\\\\\\\text{Put the value of x to the first equation.}\\\\4(-4)-y=-15\\-16-y=-15\qquad\text{add 16 to both sides}\\-y=1\qquad\text{change the signs}\\\boxed{y=-1}`