Asked by Lee

Suppose a parabola has a vertex (-4,7) and also passes through the point (-3,8) Write the equation of the parabola in vertex form.
f(x)=a(x-h)^2+k
I believe h=-4
k=7
Not sure what to do from here.
Answered by Steve
from the vertex, you know that

y = a(x+4)^2 + 7

Now just plug in (-3,8) to find a:

8 = a(1)+7
1 = a

y = (x+4)^2 + 7
Answered by Lee
I'm not sure what your saying
Answered by Steve
you seemed to be able to figure out h and k for the vertex, so what's the hangup? All I did was use your equation and use the values x=-3 and y=8 to solve for a.
Answered by Lee
y=a(x-h)^2+k
y=a(x+4)^2+7
8=a((x-3)+4)^2+7
8=a(1)^2+7
1=a
4=(x+4)^2+7
Is this right?
Answered by Steve
well, I'd say yes, since it agrees with the equation I posted above. (sort of; not sure what the 4 means)
Answered by Lee
sorry was y we have to show our steps when figuring problems thank you
Answered by Senator Armstrong
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