SOLUTION: The square of 9 more than a number is equal to 9 more than the square of the number. What is the number? thanx

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: The square of 9 more than a number is equal to 9 more than the square of the number. What is the number? thanx      Log On


   

Question 40004: The square of 9 more than a number is equal to 9 more than the square of the number. What is the number?
thanx
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Let the number be x. Then we have
(x + 9)^2 = x^2 + 9
x^2 + 18x + 81 = x^2 + 9
18x + 81 = 9
18x = -72
x = -4