Olivia was asked to factor the following expression completely:
x^3-x+3x^2y=3y
x(x^2-1)+3y(x^2-1)
(x+3y)(x^2-1)
How can you check Olivia’s work to show the answer is or is not correct. If Olivia is not correct, explain to Olivia where her mistake is and how to fix it.