Question

Find value of x and y

4.)2x-3y=-15
x=4y

Answer 1

2x - 3y = -15
x = 4y
substitute x frm eq2 to eq1
2 (4y) - 3y = -15
8y - 3y = -15
5y = - 15
y = -3
substitute y in eq2
x = 4(-3)
x = -12
y = -3 , x = -12

Answer 2

`\left\{\begin{array}{ccc}2x-3y=-15\\x=4y\end{array}\right\\\\substitute\\\\2\cdot4y-3y=-15\\8y-3y=-15\\5y=-15\ \ \ \ \ |both\ sides\ :5\\y=-3\\\\x=4\cdot(-3)=-12\\\\Solution:x=-12\ and\ y=-3.`