3(x^2-1)-(x^2-7x+10)

Question

what is this expression equivalent to

Answer 1

3(x² - 1) - (x² - 7x + 10)

3x² - 3 - x² + 7x - 10 [distributing the "-" in front of the parenthesis switches the sign for the items in the parenthesis]

2x² + 7x - 13 ["3x²" and "-x²"and "like terms"; "-3" and "-10" are "like terms"]