the zeros of the function if they are r1 and r2 the factored form is
f(x)=(x-r1)(x-r2)
so
undistribute -1
f(x)=-1(x-2)(x-(-1))(x-(-2))
3rd degree
so it goes from bottom left to top right
but the -1 flips it so it goes from top left to bottom right
plot the points x=-2, x=-1, and x=2 on x axis
draw a line (curved) that passes through (-2,0) (-1,0) and (2,0) and goes from top left to bottom right
