Above the original problem is shown
To begin working on the problem above plug in P=(-x) into the equation wherever you see (x)
After you plug in (-x) you'll get the answer above, you'll notice the sign changes as you go along which are marked by the arrows.
Above is the original, incorrect, and correct answer the problem was messed up with the middle sign change.
Above is the brace map for problem #31
This is the work for the trapezoid problem it chose to use the quadratic formula to solve the problem.