Answer:
42
Step-by-step explanation:
solve for x first
4x+6+7x+15=120
11x+21=120
120-21=99
11x=99
x=9
plug in 9 for Ab equation
4x+6
4(9)+6=42.
AC is the same as AB + AC so then you create an expression and find x. I put the working on a photo
