y=2x2+5x It is a concave up parabola because the coeffeicient of x2 is positivey=x(2x+5)
When y=0 x=0 or x=-5/2
So the roots are x=0 and x=-5/2
The axis of symmetry is the average of the 2 roots x=-5/4
When x=-5/4
y=2\times\frac{25}{16}+5\times\frac{-5}{4}\\\\ y=\frac{25}{8}+\frac{-25}{4}\\\\ y=\frac{25}{8}+\frac{-50}8}\\\\ y=\frac{-25}{8}\\\\ \mbox{ therefore}\\\\ \mbox{Vertex is }\left(-1\frac{1}{4},-3\frac{1}{8}\right)
Just as CPhill said.
Re: which data set best describe by the function y=2x squared+5x
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It's a parabola opening "upward' with its vertex at (-1.25, -3,125)
y=2x2+5x It is a concave up parabola because the coeffeicient of x2 is positivey=x(2x+5)
When y=0 x=0 or x=-5/2
So the roots are x=0 and x=-5/2
The axis of symmetry is the average of the 2 roots x=-5/4
When x=-5/4
y=2\times\frac{25}{16}+5\times\frac{-5}{4}\\\\ y=\frac{25}{8}+\frac{-25}{4}\\\\ y=\frac{25}{8}+\frac{-50}8}\\\\ y=\frac{-25}{8}\\\\ \mbox{ therefore}\\\\ \mbox{Vertex is }\left(-1\frac{1}{4},-3\frac{1}{8}\right)
Just as CPhill said.