Multiple choice

Which of the following equation has $(-1)$ as a root ?

  1. $\displaystyle x^{2}+3x-10=0$
  2. $\displaystyle x^{2}-x-12=0$
  3. $\displaystyle 3x^{2}-2x-5=0$
  4. $\displaystyle 9x^{2}+24x+16=0$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Plug x = -1 into each equation. A: 1-3-10 != 0. B: 1+1-12 != 0. C: 3(1)-2(-1)-5 = 3+2-5 = 0. D: 9-24+16 != 0.

AI explanation

Substitute x = -1 into each equation to see which one equals zero. For the equation 3x^2 - 2x - 5 = 0, substituting -1 gives 3(-1)^2 - 2(-1) - 5, which results in 3 + 2 - 5 = 0. Therefore, -1 is a root of this equation.

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