7.
7x +13 = 8x - 8
8x - 7x = 13 + 8
x = 21
7x +13 = 7(21) + 13 = 160
160+160 = 320
360 - 32 = 40
so A = C = 20
answer. 20 (third choice)
# 8.
AB = CD
3x+2 = 4x-3
4x-3x = 2+3
x = 5
AB = 3x+2 = 3(5) + 2 = 17
answer" 17 (third choice)
# 13.
BE = ED
3x + 1 = 5x - 9
5x - 3x = 1 + 9
2x = 10
x =5
answer : 5 (third choice)
#14
x = 53, y = 106 (second choice)
