Question

Solve this sumutaneous equation
2x-5 y=9
3x+4y=2

Answer 1

x = 2 and y = -1 → (2, -1)

Explanation:

`\left\{\begin{array}{ccc}2x-5y=9&\text{multipy both sides by 4}\\3x+4y=2&\text{multiply both sides by 5}\end{array}\right\\\underline{+\left\{\begin{array}{ccc}8x-20y=36\\15x+20y=10\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad23x=46\qquad\text{divide both sides by 23}\\.\qquad x=2\\\\\text{put it to the second equation}\\\\3(2)+4y=2\\6+4y=2\qquad\text{subtract 6 from both sides}\\4y=-4\qquad\text{divide both sides by 4}\\y=-1`