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

Question

3 years ago

9

0 5x 2 + 20x + 20 = 0 x 2 - x - 6 = 0

2 answers:

Olin [163] · Answer 1 · 2022-09-02T22:50:07+03:00

Olin [163]3 years ago

7 0

The equations which have only one solution are: x²+6x+9=0 and 5x²+20x+20=0,

Phoenix [80] · Answer 2 · 2022-09-03T00:05:16+03:00

Answer:

2nd and 4th equation will have only one solution.

Step-by-step explanation:

1). 4x² + 4x = 0

4x(x + 1) = 0

x = 0

or (x + 1) = 0 ⇒ x = -1

2). x² + 6x + 9 = 0

(x + 3)² = 0

(x + 3) = 0

x = -3

3). 9x² - 25 = 0

9x² = 25

x² = $\frac{25}{9}$

x = ± $\sqrt{\frac{25}{9} }$

x = ± $\frac{5}{3}$

4). 5x² + 20x + 20 = 0

5(x² + 4x + 4) = 0

(x + 2)²= 0

x + 2 = 0

x = -2

5). x² - x - 6 = 0

x² - 3x + 2x - 6 = 0

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

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

x = -2 or x = 3

Therefore, 2nd and 4th equations have only one solution.