Trig question

[TonyC]

I have a couple hundred homework problems that are truely problems. I have been out of school for a while and really need help.

Find the equation for the parabola with the given vertex that passes through the given point: vertex(-5,5) point: (-3,17)

Please help...
I came up with the following:
y=11/32(x-5)^2 + 5

Not sure if I am even close. :?:

 

[tkhunny]

You are in the neighborhood. Start by writing down the basiv formula you have in your head.

y-k = r*(x-h)

Vertex: (h,k) = (-5,5)

y-5 = r*(x-(-5))² <== There's where you wandered off.
y-5 = r*(x+5)² <== Now plug in x = -3 and y = 17 and solve for r.

Note: This problem is ambiguous. I hope there is more to the problem statement than you have provided. After you find the value of 'r' in the equation above, take a look at (x+5) = (1/72)*(y-5)². This is also a parabola with vertex at (-5,5) and passing through (-3,17).

Edit: "squares" added.

 

[TonyC]

As I go through this problem, I have come up with:
y=3/16(x-5)^2+5

Please help :?:

 

[tkhunny]

As I go through this problem, I have come up with:
y=3/16(x-5)^2+5

How did you get that?

y-5 = r*(x+5)²

Substitute x = -3, y = 17

17-5 = r*(-3+5)²

Solve for 'r'

12 = r*(2)²
12 = r*(4)
3 = r

y-5 = 3*(x+5)² -- There it is.

Don't forget to point out to your teacher that this problem statement, as presented, has two solutions.