Answer:
The value of x is 3
Explanation:
∵ Quadrilateral ABCD is congruent to quadrilateral JKLM
∴ AB = JK and BC = KL
∴ CD = LM and AD = JM
∵ BC = 8x + 7
∵ KL = 31
∵ BC = KL
→ Equate their right sides
∴ 8x + 7 = 31
→ Subtract 7 from both sides
∵ 8x + 7 - 7 = 31 - 7
∴ 8x = 24
→ Divide both sides by 8 to find x
∴
=

∴ x = 3
∴ The value of x is 3