Answer:
y = -10
Explanation:
4x - 4y = 12
Substitute the x with -7, since it has been given.
4(-7) - 4y = 12
-28 - 4y = 12
Add 28 onto both sides
-28 + 28 - 4y = 12 + 28
-4y = 40
Divide by -4 to isolate the variable
-4y/-4 = 40/-4
y = - 10
Check:
Substitute the y and x
4x - 4y = 12
4(-7) - 4 ( -10 ) = 12
-28 + 40 = 12
12 = 12
or.....
try to see if x stays as -7
4x - 4y = 12
4x - 4 (-10) = 12
4x + 40 = 12
Subtract 40 onto both sides
4x + 40 - 40 = 12 - 40
4x = -28
Divide by 4 onto both sides to isolate the variable
4x/4 = -28/4
x = -7
And it's correct
Hope this helped!