Answer:
x = -10, -8
Step-by-step explanation:
x^2+18x+80=0
Subtract 80 from each side
x^2+18x=-80
Take the coefficient of x
18
Divide by 2
18/2 = 9
Square it
9^2 =81
Add 81 to each side
x^2+18x +81=-80+81
(x+ 9) ^2 = 1
Take the square root of each side
sqrt((x+ 9) ^2 )=±sqrt( 1)
x+9 = ±1
Subtract 9 from each side
x+9-9= -9 ±1
x = -9+1 x = -9-1
x = -8 x = -10
