SOLUTION: What does x equal when (5x+5)^1/2-5=3x

Algebra ->  Radicals -> SOLUTION: What does x equal when (5x+5)^1/2-5=3x      Log On


   

Question 304563: What does x equal when
(5x+5)^1/2-5=3x
Answer by CharlesG2(834) About Me  (Show Source):
You can put this solution on YOUR website!
What does x equal when
(5x+5)^1/2-5=3x
(5x + 5)^1/2 = 3x + 5 (square both sides)
5x + 5 = (3x + 5)^2 (use FOIL on right side)
5x + 5 = (3x)^2 + 2*3*5*x + 25
5x + 5 = 9x^2 + 30x + 25
0 = 9x^2 + 25x + 20
use quadratic formula, a=9, b=25, c=20
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-25+%2B-+sqrt%2825%5E2+-+4%2A9%2A20%29%29%2F%282%2A9%29+
x+=+%28-25+%2B-+sqrt%28625+-+720%29%29%2F18+
x+=+%28-25+%2B-+sqrt%28-95%29%29%2F18+
x+=+%28-25%2F18%29+%2B-+sqrt%28-1+%2A+95%29%2F18+
x+=+%28-25%2F18%29+%2B-+%28sqrt%2895%29%2F18%29i+
x+=+-1.3889+%2B-+0.5415i+
rounded to 4 places