SOLUTION: How do you write the equation for a parabola opening downward with a y intercept of 7?

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Question 1062994: How do you write the equation for a parabola opening downward with a y intercept of 7?
Found 2 solutions by stanbon, josgarithmetic:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
How do you write the equation for a parabola opening downward with a y intercept of 7?
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y = -x^2 + 7
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Cheers,
Stan H.
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Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
a%3C0 for parabola to open downward.
system%28y=a%28x-h%29%5E2%2Bk%2Ca%3C0%29

You can pick any value for a that you want but it must be a negative value.

y-intercept 7
The point (0,7).
a%280-h%29%5E2%2Bk=7
but your vertex (h,k) is also still a variable.


You specified only two things. You could pick a specific factor a and vertex (h,k). What if the vertex were also chosen to be the y-intercept?
What if a=-1?
-1%28x-0%29%5E2%2B7=y
y=-x%5E2%2B7------------just one example that fits.