Posted by Lee on .
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(xh)^2+k
I believe h=4
k=7
Not sure what to do from here.

algebra 
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 
algebra 
Lee,
I'm not sure what your saying

algebra 
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.

algebra 
Lee,
y=a(xh)^2+k
y=a(x+4)^2+7
8=a((x3)+4)^2+7
8=a(1)^2+7
1=a
4=(x+4)^2+7
Is this right? 
algebra 
Steve,
well, I'd say yes, since it agrees with the equation I posted above. (sort of; not sure what the 4 means)

algebra 
Lee,
sorry was y we have to show our steps when figuring problems thank you