Answer:
y = -3, x = 9
Explanation:
ISOLATE THE X
step 1) subtract 4y from both sides.
x + 4y - 4y = -3 - 4y
step 2) simplify
x = -3 - 4y
step 3) substitute x = -3 - 4y
-3 - 4y + 7y = -12
ISOLATE THE Y
step 4) Add similar elements: -4y + 7y = 3y
-3 - 4y + 7y = -12
step 5) Add 3 to both sides
-3 + 3y + 3 = -12 + 3
step 6) Simplify
3y = -9
step 7) Divide both sides by 3
3y/3 = -9/3
step 8) you now know y = -3
step 9) substitute y = -3 in for x = -3 - 4y
x = -3 - 4(-3)
step 10) negative times a negative equals a positive
x = -3 + 12
step 11) add -3 by 12 to get x = 9
step 12) you now have found the answer x = -3 and y = 9