Question

Rewrite the function by completing the square r^2+18x+80=0

Answer 1

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