remember that x^2=positive unless x is an imaginary number
so you have
x and y
x=input
y=output/result aka g(x) or f(x) or such
(x,y)
so what you do is
at the top of each pair of rows you see a set of values
+/- 1 means input the positive 1 and negative 1 and see what happens
the result goes in the row directly below it
so example
f(x)=x^2
we are given
0,1,2,3 to input
since it is squred, the negatives and positives are all going to be positive
f(0)=0^2=0
f(1)=1^2=1
f(2)=2^2=4
f(3)=3^2=9
f(0)=0^2=0
f(-1)=(-1)^2=1
f(-2)=(-2)^2=4
f(-3)=(-3)^2=9
so you plot the points
(0,0) (1,1) (2,4) (3,9) (-1,1) (-2,4) (-3,9)
you can do the rest
I will show examples of each
g(x)=-2x^2 means lets say you had 3
g(3)=-2(3^2)=-2(9)=-18
h(x)=1/4x^2
h(3)=1/4(3^2)=1/4(9)=9/4
