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

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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(2101) 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