College Algebra: x + 2sqrtx - 80 = 0

[Guest]

x + 2sqrtx - 80 = 0

(sqrtx - 8)(sqrt + 10) = 0

sqrtx - 8 = 0 or sqrtx + 10 = 0
sqrtx = 8. . .or. . .sqrtx = -10
x = 8. . .or. . .-10 has no real solution

Please help. There is no square root of 8. What am I doing wrong?

 

[galactus]

Re: College Algebra

x+2sqrtx-80=0
(sqrtx-8)(sqrt+10)=0
sqrtx-8=0 or sqrtx+10=0
sqrtx=8 or sqrtx=-10Here
x=8 or -10 has no real solution

Please help there is no square root of 8....what am I doing wrong?

You just need one more step.

\(\displaystyle \L\\\overbrace{\sqrt{x}=8}^{x=64}\;\ or\;\ \overbrace{\sqrt{x}=-10}^{extraneous}\)