Identify the solutions to the quadratic equation

x2 + 4x-21 = 0

Check all that apply

O A. x = 3

B. X = - 7

O C. x = 21

O D. x = - 5

O E. x = 4

A. x=3

B. x=-7

Step-by-step explanation:

Hi, to answer this question we have to apply the quadratic formula:

For: ax2 + bx + c

x = [ - b ± √b²-4ac] / 2a

Replacing with the values given:

x = [ - 4 ± √ (4) ²-4 (1) - 21] / 2 (1)

x = [-4 ± √16 + 84] / 2

x = [ - 4 ± √100] / 2

x = [ - 4 ± 10] / 2

Positive:

x = [-4 + 10] / 2 = 6 / 2 = 3

Negative:

x = [ - 4 - 10] / 2 = - 14/2 = - 7

So, the solutions are:

A. x=3

B. x=-7

Feel free to ask for more if needed or if you did not understand something.