I'm working on the same thing right now and I'm using every resource in my hands right now to find a solution. I will edit this post when I have more. If you need any more help I have completed the previous activity and most of this one.
EDIT:
Ok so I checked with somebody who is pretty good with math and they said that 5x=5x would be right. Not too sure but that's what I'm putting.
I put EVERYTHING for this assignment in comments down below. Geez all of this for 5 freakin points.
See the attached figures.
The area of this trapezoid = 576
cm²
-2a+2=22
3(a+4)-5(a-2)=22
3a+12-5a-10=22
-2a+12-10=22
-2a+2=22
D, add all your answers than divide by how many numbers there are