The problem
Click to see the original problem
"This calculation is taking too much CPU time." is the message that popped up for me. Even though it's just 10th-grader-level mathematics.
Answer provided by our tutors
I will pass this on to the developer but it is not designed for a manual solution. One resource is to manually manipulate the expression into a simpler form and then enter the equation into the 'Advanced' link on quickmath.com:
The 3rd degree expression was obtained by first reaching an initial solution step using doyourmath.com:
