Answer:
x =-2 ±2 sqrt(6)
Step-by-step explanation:
x^2+4x=20
Take the coefficient of x
4
Divide by 2
4/2 =2
Then square it
2^2 =4
Add this to each side
x^2+4x +4=20+4
x^2+4x +4=24
Take the 4/2 and rewrite as (x+2)^2
(x+2)^2 = 24
Take the square root of each side
sqrt((x+2)^2) = ± sqrt(24)
x+2 =± sqrt(24)
Subtract 2 from each side
x+2-2 =-2 ± sqrt(24)
x =-2 ± sqrt(24)
We can simplify sqrt(24) as = sqrt(4*6) = 2sqrt(6)
x =-2 ±2 sqrt(6)
