Answer:
14
Explanation:
5x + 12 = 7x - 16
28 = 2x
14 = x
Angle 3's alternate interior angle is Angle 2. Angle two is equal to angle 4 (thi is just a rule in geometry). So that means Angle 3 is also equal to angle $. So just make the equations equal to eachother and solve for x as shown above.