Question

Solve the elimination. 5x+7y=-1 4x-2y=22

Answer 1

$\left\{\begin{array}{ccc}5x+7y=-1&\text{multiply both sides by 2}\\4x-2y=22&|\text{multiply both sides by 7}\end{array}\right\\\underline{+\left\{\begin{array}{ccc}10x+14y=-2\\28x-14y=154\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad38x=152\qquad\text{divide both sides by 38}\\.\qquad \boxed{x=4}\\\\\text{Put the value of x to the first equation:}\\\\5(4)+7y=-1\\20+7y=-1\qquad\text{substract 20 from both sides}\\7y=-21\qquad\text{divide both sides by 7}\\\boxed{y=-3}\\\\Answer:\ \boxed{x=4\ and\ y=-3\to(4,\ -3)}$