SOLUTION: ax^2+bx+c=y. data points are (0,0),(4,7)and (-4,9) find values for ab and c to make a general quadratic function for which is true.

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Question 420107: ax^2+bx+c=y. data points are (0,0),(4,7)and (-4,9) find values for ab and c to make a general quadratic function for which is true.
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
(0,0) ==> a%2A0%5E2+%2B+b%2A0+%2B+c+=+0 ==> c = 0.
(4,7) and (-4, 9) ==> 16a + 4b = 7, and 16a - 4b = 9 by direct substitution.
Adding corresponding sides, we get
32a = 16, or a = 1/2.
Substituting this a value into 16a + 4b = 7, we get b = -1/4.
Then ab = -1/8.