Multiple choice

For the equation $\mid x\mid ^{2} + \mid x \mid - 6 = 0$

  1. there is only one root

  2. the sum of the roots is $1$
  3. the sum of the roots is $0$
  4. the product of the roots is $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let u = |x|. The equation becomes u^2 + u - 6 = 0, which factors to (u+3)(u-2) = 0. Since u = |x| must be non-negative, u = 2. Thus |x| = 2, so x = 2 or x = -2. The sum of the roots is 2 + (-2) = 0.

AI explanation

Substitute y equals the absolute value of x into the equation to get the quadratic y squared plus y minus 6 equals 0. Factoring this gives y plus 3 times y minus 2 equals 0, yielding y equals 2 or y equals negative 3; since the absolute value of x cannot be negative, the absolute value of x equals 2. This gives two real roots for x, which are 2 and negative 2, making their sum equal to 0.