Answer:
x = -2 ±sqrt( 19)
Step-by-step explanation:
x^2 + 4x = 15
Take the coefficient of x
4
Divide by 2
4/2 =2
Square it
2^2 = 4
Add it to each side
x^2 + 4x+4 = 15+4
(x+2)^2 = 19
Take the square root of each side
sqrt( (x+2)^2) =±sqrt( 19)
x+2 = ±sqrt( 19)
Subtract 2 from each side
x+2-2 = -2 ±sqrt( 19)
x = -2 ±sqrt( 19)
