SOLUTION: I have a question Simplify by factoring. {{{sqrt(48a^2b)}}} Simplify {{{3 sqrt(-1/125)}}} Solve {{{sqrt(5x+21)=x+3}}}

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I have a question Simplify by factoring. {{{sqrt(48a^2b)}}} Simplify {{{3 sqrt(-1/125)}}} Solve {{{sqrt(5x+21)=x+3}}}      Log On


   

Question 438741: I have a question
Simplify by factoring. sqrt%2848a%5E2b%29
Simplify 3+sqrt%28-1%2F125%29
Solve sqrt%285x%2B21%29=x%2B3
Answer by unlockmath(1688) About Me  (Show Source):
You can put this solution on YOUR website!
Hello,
I'll help you with the last one.
sqrt(5x+21)=x+3
First off we can square both sides to
5x+21=(x+3)^2
Expand this out:
5x+21=x^2+6x+9
Subtract 5x and 21 to get:
x^2+x-12=0
Factor
(x-3)(x+4)=0
Solve for x
x=3
x=-4
So we find that 3 works in the equation.
Make sense?
RJ
www.math-unlock.com