39
А
В
с
9х+7
- 3x+20

x=2

Step-by-step explanation:

We are given that the length of the line segment AC is 39. We are also given the length segment of AB = 9x+7 and the line segment BC is equivalent to -3x+20.

We also know based off the diagram that AC = AB + BC. We can use substitution to set up an equation:

AB+BC=AC

9x+7-3x+20=39

Combine like terms

6x+27=39

Subtract 27 from both sides

6x=12

Divide both sides by 6 to isolate x

x=2