SOLUTION: Write a system of equations and solve: The curve y=ax^2+bx passes through (2,0) and (4,8). Find a and b.

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Question 777170: Write a system of equations and solve:
The curve y=ax^2+bx passes through (2,0) and (4,8). Find a and b.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The curve y=ax^2+bx passes through (2,0) and (4,8). Find a and b.
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(2,0) gives the equation:: 0 = 4a + 2b
(4,8) gives the equation:: 8 = 16a+ 4b
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Modify for elimination:::
8a + 4b = 0
16a+ 4b = 8
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Subtract and solve for "a":
8a = 8
a = 1
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Solve for "b":
4a + 2b = 0
4 + 2b = 0
b = -2
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Equation: y = x^2 -2x
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Cheers,
Stan H.