Question

Solve (x + 3)(x – 3) = 40. Identify any double roots.

A. {3, –3}

B. {7, –7}

C. {0, 3, –3}

D. {0, 7 (double root)}

Is it A or C and why?

Answer 1

Take the following steps to solve this:
Step 1. Multiply and clear the parentheses. It is a special product and you could do it in your head.
Getting x^2 - 9 = 40 Simplify further getting x^2=40 + 9 = 49
Step 2 solve for x \[x = \sqrt{49}\]Taking the square root of both sides.