Which of the following equations have only one solution? Select all correct answers x²-x-6=0 5x^2 + 20 x + 20 = 0 9x^2 - 25 = 0 4x^2 + 4 x = 0 x^2 + 6 x + 9 = 0

Question

asked Nov 6, 2021 113k views

2 Answers

Sup · Answer 1 · 2021-11-08T07:14:02+0000

Answer: 5x^2 + 20x + 20 = 0 and

x^2 + 6x + 9 = 0

Explanation:

x^2 - x - 6 = 0

(x + 2) (x - 3) = 0

x = -2, 3 (two solutions)

5x^2 + 20x + 20 = 0

5(x^2 + 4x + 4) = 0

5 (x + 2)^2

x = -2 (one solution)

9x^2 - 25 = 0

(3x - 5) (3x + 5) = 0

x = +/- 5/3 (two solutions)

4x^2 + 4x = 0

4x (x + 1) = 0

x = 0, -1 (two solutions)

x^2 + 6x + 9 = 0

(x + 3)^2 = 0

x = -3 (one solution)