SOLUTION: Find an equation of the fom y=ax^2+b whose graph passes through the points (-1,1) and (2,7). Please help.

Question 354010: Find an equation of the fom y=ax^2+b whose graph passes through the points (-1,1) and (2,7).
Please help.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Find an equation of the fom y=ax^2+b whose graph
passes through the points (-1,1) and (2,7).
----
Substitute each x/y pair into the equation so
you can solve for "a" and for "b".
--------
1 = a + b
7 = 4a+b
-----
Subtract the 1st from the 2nd and solve for "a":
6 = 3a
a = 2
------
Since 1 = a+b, b = 1-2 = -1
----
Equation:
y = 2x^2-1
===================
Cheers,
Stan H.
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