Question

Which of the following equations have only one solution? Select all correct answers.

x²-x-6=0
5 x2 + 20 x+ 20 = 0
9x2 - 25 = 0
4x2+4 x=0
12+ 6 x+9= 0​

Answer 1

5x^2 + 20x + 20 = 0

12+ 6x +9= 0​

Explanation:

5x^2 + 20x + 20 = 0 /5 12 + 6x + 9 = 0

x^2 + 4x + 4 = 0 6x = -9-12

(x+2)^2=0 6x = -21

x + 2 = 0 x = -21/6

x=-2 x = -3.5

Answer 2

The equations which have only one solution is: 5x²+20x+20=0,

Explanation: