SOLUTION: a number is 72 less than its square.find all such numbers

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Question 268064: a number is 72 less than its square.find all such numbers
Answer by CharlesG2(834) About Me  (Show Source):
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a number is 72 less than its square.find all such numbers
a number x
x^2 - 72 = x
x^2 - x - 72 = 0
(x + 8)(x-9) = 0 (foil: x^2 - 9x + 8x -72)
x = -8 or x = 9