Question

Solve the following equation by completing the square.
x^2+8x+7=0
Find x

Answer 1

x^2+8x+7=0
\[(x+4)^2-16-7=0\]
\[(x+4)^2-23=0\]
\[(x+4)^2=23\]
\[x+4= \pm \sqrt{23}\]
Subtract both sides by 4 and you're done

Answer 2

x^2+8x+7=0
x^2+2*x*4+16-16+7=0 [i have added 16 and subtracted 16 not altering the eqn]
(x^2+2*x*4+16)-16+7=0
(x+4)^2 -9=0
(x+4)^2 =9=(+-3)^2
x+4=+-3
x=(+-3)-4
x=(+3-4) or (-3-4)
x=-1 or -7

Answer 3

Got it?

Answer 4

yes, thank you, I did get it :)