Answer:
EC = 64
CD = 128
Step-by-step explanation:
AB bisects CD at E. So, EC = ED
EC + ED = CD
EC + EC = CD
2*(EC) = CD
2* (5x + 9) = 13x - 15
2*5x + 2*9 = 13x - 15
10x + 18 = 13x - 15
Subtract 10x from both sides
18 = 13x - 10x - 15
18 = 3x - 15
Add 15 to both sides
18 + 15 = 3x
33 = 3x
3x = 33
Divide both sides by 3
x =33/3
x = 11
Length of EC = 5x + 9 = 5*11 + 9 = 55 + 9 = 64
CD = 13x - 15 = 13*11 - 15 = 143 - 15 = 128
