Determine an equation for this parabola

Såxon · #1 $Old$ January 25th, 2009, 08:30 PM

A graph of a parabola has a line of symmetry X=3 and contains the points (1,0) and (4,-3) Determine an equation for this parabola.

using y=a(X-h)^2+K

-3 = a(4-1)^2 + 0
-3 = -1/3(4-1)^2 + 0

did i work this correctly?
thanks

Jhevon · #2 $Old$ January 25th, 2009, 08:48 PM

Quote:

Originally Posted by Såxon $View Post$

A graph of a parabola has a line of symmetry X=3 and contains the points (1,0) and (4,-3) Determine an equation for this parabola.

using y=a(X-h)^2+K

-3 = a(4-1)^2 + 0
-3 = -1/3(4-1)^2 + 0

did i work this correctly?
thanks

um, no

our parabola is of the form $y = a(x - 3)^2 + k$

since $(1,0)$ is on the graph, we have

$0 = a(1 - 3)^2 + k$ .................(1)

since $(4,-3)$ is on the graph, we have

$-3 = a(4 - 3)^2 + k$ ................(2)

thus we have two simultaneous equations with two unknowns. solve this system to find your parabola