SOLUTION: I don't understand how to complete this problem: Write an equation for the parabola whose vertex is at (2,6) and which passes through (4,-1).

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: I don't understand how to complete this problem: Write an equation for the parabola whose vertex is at (2,6) and which passes through (4,-1).      Log On


   

Question 1010890: I don't understand how to complete this problem: Write an equation for the parabola whose vertex is at (2,6) and which passes through (4,-1).
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The vertex form is y=a(x-h)^2+k, where the vertex is (h,k)
That means y=a(x-2)^2+6
Now, use the point given to solve for a.
-1=a(2)^2+6, (x-2)^2=2^2, if x=4
-1=4a+6
4a=-7
a=(-7/4)
(-7/4){x^2-4x+4)+6=
-(7/4)x^2+7x-7+6=-(7/4)x^2+7x-1
graph%28300%2C300%2C-10%2C10%2C-10%2C10%2C-%287%2F4%29x%5E2%2B7x-1%29