SOLUTION: Three times the square of a certain positive number exceeds six times the number by nine. Find the number:

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Question 1143690: Three times the square of a certain positive number exceeds six times the number by nine. Find the
number:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


3x%5E2+=+6x%2B9

It's a quadratic equation; set one side equal to zero and factor if possible.

3x%5E2-6x-9+=+0
x%5E2-2x-3+=+0
%28x-3%29%28x%2B1%29+=+0

x=3 or x=-1

The problem specifies a positive solution, so x=3.

CHECK:
3x^2 = 3(3^2) = 3*9 = 27
6x+9 = 6(3)+9 = 18+9 = 27