Question

What is the value of x?



Enter your answer in the box.

x =

Answer 1

Explanation:

9 cm/72 cm=3x-20/56

3x-20=56/8. (9÷72=1/8)

3x-20=7

3x=7+20

3x=27

x=27/3

x=9

Answer 2

First set up a proportion because they are similar triangles:
9/3x-20 = (72+9)/(56+3x-20)
9/3x-20 = 81/3x+36
9(3x+36) = 81(3x-20)
27x+324 = 243x-1620
1944 = 216x
x = 9