Question

Which of the following is equal to the rational expression when x≠5 or -1?

(x-7)(x + 1)
(x + 1)(x - 5)

Answer 1

Answer: (x-7)/(x-5)

The (x+1) terms divide and cancel out due to the rule that x/x = 1, when x is nonzero. In that rule, we can replace 'x' with any algebraic expression we want.