How do you solve using the completing the square method x^2+8x-9=0?
1 Answer
Mar 18, 2016
Completing the square is designed to give you a perfect square trinomial on the left of an equation.
Explanation:
-
Get any constants on the right side.
x^2+8x=9 -
Add
(b/2)^2=(8/2)^2 to both sides
x^2+8x+16=9+16 -
Factor the left.
(x+4)^2=25 -
Square root both sides.
(x+4)=+-5 -
x={5-4,-5-4} = {1,-9}