Could anyone be willing to help me on my homework assignment? :)

After the last step, you have to plug x into the equations. 5(5)+8=33 and 8(5)-1=39. You do this because it asks you to find the measurements of the angles, meaning the whole thing, not just x. To check, you add the two values of EFG and EFH, and they should equal EFG. 33+39=72, so it all checks out!

The answer here would be 10

I'm not sure you can get negative in holes, but in the case of -3+5=2the total is 2.