Answer:
x=2
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