Answer:
x = 7
Explanation:
If L is parallel to M, therefore:
7x - 7 = 4x + 14 (alternate interior angles are congruent)
7x - 7 - 4x = 4x + 14 - 4x (subtraction property of equality)
3x - 7 = 14
3x - 7 + 7 = 14 + 7 (addition property of equality)
3x = 21
Divide both sides by 3
x = 7