Polynomial equations

[spardawg]

Write the formula for a parabola with a vertex at (-5, 10) that is upside-down and goes through the origin (0, 0).

So, I know the graph has to have 2 roots, or where the graph crosses the x-axis, because it end the same way. I also know that the a-value is negative because it starts and ends negative. And the vertex is the max point. Please, help!!

Thanks,
Spardawg

 

[galactus]

\(\displaystyle y=a(x-h)^{2}+k\), where (h,k) is the coordinates of the vertex.

\(\displaystyle 0=a(0-(-5))^{2}+10\)

\(\displaystyle a=\frac{-2}{5}\)

\(\displaystyle y=\frac{-2}{5}(x+5)^{2}+10=\frac{-2}{5}x^{2}-4x\)

 

[spardawg]

okay, I get it now!! Thank youu