SOLUTION: Find the equation of the parabola in the form of y = a(x-p)(x-q), given the points are (-2,21), (-1,0) and (5,0).

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Question 1118696: Find the equation of the parabola in the form of y = a(x-p)(x-q), given the points are (-2,21), (-1,0) and (5,0).
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39799) About Me  (Show Source):
You can put this solution on YOUR website!
Two of the given points are the zeros.

y=a%28x%2B1%29%28x-5%29

The other, non-root point, will establish the leading coefficient.
a=y%2F%28%28x%2B1%29%28x-5%29%29
a=21%2F%28%28-2%2B1%29%28-2-5%29%29
a=21%2F%28-1%28-7%29%29
a=21%2F7
a=3
-
system%28y=3%28x%2B1%29%28x-5%29%2Cor%2Cy=3%28x-%28-1%29%29%28x-5%29%29

Answer by MathTherapy(10809) About Me  (Show Source):
You can put this solution on YOUR website!

Find the equation of the parabola in the form of y = a(x-p)(x-q), given the points are (-2,21), (-1,0) and (5,0).
y = a(x – p)(x – q)

Substitute - 1 for p, 5 for q, and (- 2, 21) for (x, y) in the above equation.

This should result in a = 3

Then substitute 3 for a, - 1 for p, and 5 for q in the above equation.



Correct equation:  highlight_green%28matrix%281%2C3%2C+y%2C+%22=%22%2C+3%28x+%2B+1%29%28x+-+5%29%29%29

IGNORE all other USUAL WRONG answers!