Can someone show me step by step?

Answer:
AB = JK = 49
Step-by-step explanation:
Since ABC = JKL
We know the length of AB has to equal the length of JK.
AB = JK
14x+7 = 5x+34
Subtract 5x from each side.
14x-5x +7 = 5x-5x+34
9x+7 = 34
Subtract 7 from each side
9x+7-7 = 34 -7
9x = 27
Divide each side by 9.
9x/9 = 27/9
x =3
AB = 14x+7
Substitute x=3
14(3) +7
42+7
AB = 49