7) BC + CD = BD
(4x - 29) + (5x-9) = 7x -10
9x - 38 = 7x - 10 (when you transpose you change the sign)
9x - 7x = - 10 + 38
2x = 28
x = 14
8) BD = BC
5x - 26 = 2x + 1
5x - 2x = 1 +26
3x = 27
x = 9
if x = 9, then BC = 2x + 1 = 2(9) + 1 = 19
or
AB = AC - BC
AB = 43 - 19
AB = 24
