Question

HELP NEEDED ASAP. "ONLY ANSWER IF YOU KNOW THE ANSWER"

Solve the equation by completing the square.
x^2 + 10x= -81

Answer 1

x =-5± 2i sqrt(14)

Explanation:

x^2 + 10x= -81

Take the coefficient of x and divide by 2

10/2 = 5

Square it

5^2 =25

add to each side

x^2 + 10x+25 = -81+25

( x+5) ^2 = -56

Take the square root of each side

sqrt(( x+5) ^2) =± sqrt(-56)

x+5 = ± sqrt(-1) sqrt(4*14)

x+5 =± i sqrt(4)sqrt(14)

x+5 =± i 2 sqrt(14)

Subtract 5 from each side

x+5-5 =-5± i 2 sqrt(14)

x =-5± 2i sqrt(14)