Sagot :
[tex]7x-xy=-18\ \ \ \ and\ \ \ \ \ x=-4\\\\7\cdot(-4)-(-4)y=-18\\-28+4y=-18\\4y=-18+28\\4y=8\ \ \ \ \ \ \ |:4\\y=2[/tex]
7x - xy = -18 x = -4
First, fill the -4 in where the "x's" are.
7(-4) - (-4)y = -18
Then, add the 28 over.
-28 + 4y = -18
+28 +28
4y = 10
Then, get the variable by itself, so you would divide the 4 over.
4y = 10
÷4 ÷4
y = 2.5
First, fill the -4 in where the "x's" are.
7(-4) - (-4)y = -18
Then, add the 28 over.
-28 + 4y = -18
+28 +28
4y = 10
Then, get the variable by itself, so you would divide the 4 over.
4y = 10
÷4 ÷4
y = 2.5