SOLUTION: solve <a href="http://www.codecogs.com/eqnedit.php?latex=\sqrt{5x@plus;21}=x@plus;3" target="_blank"><img src="http://latex.codecogs.com/gif.latex?\sqrt{5x+21}=x+3" title="\sqrt{5

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: solve <a href="http://www.codecogs.com/eqnedit.php?latex=\sqrt{5x@plus;21}=x@plus;3" target="_blank"><img src="http://latex.codecogs.com/gif.latex?\sqrt{5x+21}=x+3" title="\sqrt{5      Log On


   

Question 404411: solve
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
sqrt%285x%2B21%29+=+x+%2B+3.......to the second power

%28sqrt%285x%2B21%29%29%5E2+=+%28x+%2B+3%29%5E2
5x%2B21+=+x%5E2+%2B+6x+%2B+9

0+=+x%5E2+%2B+6x+-+5x+-21%2B+9...or
x%5E2+%2B+6x+-+5x+-21%2B+9+=+0
x%5E2+%2B+x++-12+=+0.....use quadratic formula and plug in a=1,+%0D%0A%0D%0Ab=1, and c=-12

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%28-1+%2B-+sqrt%28+1%5E2-4%2A1%2A%28-12%29+%29%29%2F%282%2A1%29+

x+=+%28-1+%2B-+sqrt%28+1+%2B+48+%29%29%2F2+

x+=+%28-1+%2B-+sqrt%28+49+%29%29%2F2+
x+=+%28-1+%2B-++7+%29%2F2+

x1+=+%28-1+%2B+7+%29%2F2+
x1+=+6+%2F2+
x1+=+3+

x2+=+%28-1+-7+%29%2F2+
x2+=+%28-8+%29%2F2+
x2+=+-4+


check:
sqrt%285x%2B21%29+=+x+%2B+3........plug in x1+=+3+

sqrt%285%2A3%2B21%29+=+3+%2B+3

sqrt%2815%2B21%29+=+6
sqrt%2836%29+=+6
6+=+6