Answer:
True, every step that was done is correct.
Step-by-step explanation:
Since that whole line of AC equals 40, and that (4x+4)+(5x) also equals the whole line, you can just do it this way: (4x+4)+(5x)=40 Solve for x and x will equal 4. I even used an algebra calculator to solve for x and the calculator indeed said that x=4 (the image is shown below on the calculator I used to solve for x).
Hope this helped! :)