How do you solve 8x^2+32x-248x2+32x24 by completing the square?

1 Answer
Mar 20, 2017

x = -2 +sqrt 7, -2 - sqrt 7x=2+7,27

Explanation:

8 x^2 + 32 x - 24 =08x2+32x24=0

reduce coefficient x^2x2 to 1 by dividing with 88
x^2 +4x -3 = 0x2+4x3=0

consider coefficient of xx and divide by 2 then make a parentesis and square them, then square the number in parentesis and deduct it in the equation.
(x + 2)^2 - (2)^2 - 3 = 0(x+2)2(2)23=0
(x + 2)^2 - 4 - 3 = 0(x+2)243=0
(x + 2)^2 - 7 = 0(x+2)27=0
(x + 2)^2 = 7(x+2)2=7
(x + 2) = +-sqrt 7(x+2)=±7
x = -2 +-sqrt 7x=2±7

x = -2 +sqrt 7, -2 - sqrt 7x=2+7,27