I know how to graph polynomial functions, but i'm having a hard time getting the second point on this one.

Question

f(x)=x(x-1)(x+2)(x+2).
I graphed my zeros and made the right arrow go up and the left arrow go down. I plotted my first point by pluggin in -1. My first point is (-1,2). On my answer sheet there is a point at (1,-1.5). How do i know that i need to solve for another point? And how to i get the point (1, -1.5)?

Answer 1

highest x power is x^4, even, always + so
as x gets big -, f gets big +
as x gets big +, f gets big +
so I do not understand your little arrow on the left.
Now as far as I know, f(x) is 0 at x = 1, so there is no point at (1,-1.5)
however guessing what might be intended if x = -1.5, f(-1.5) =
(-1.5)(-2.5)(.5)(.5)
= .9375
oh well, I do not know why you see that point in the answer.

Answer 2

there is a point and actually the point is (.5,-1.5). Would that make more sense? Thanks for your help

Answer 3

well, try that point
f(.5) = .5*-.5*2.5*2.5 = -1.56
so I get
(.5, -1.56)