GMAT Math Practice Test #1

Answer C

This is a quadratic equation. Use the formula if and b are solutions of a quadratic equation then it can be expressed as x2 + (a-b) x - ab = 0 or (x+a) (x-b) = 0

Given: x+6 is a factor

So: a= 6; (a-b) = m; and ab =-48

Hence b = 8 and m =2

Key takeaway: The general form of a quadratic equation is x2 + (a+b) x + ab = 0 and can be expressed as product of two terms (x+a)(x+b) = 0, a and b are called two roots or solutions of the equation The values x =a or b satisfy the equation.