Use three different ways (graph, table, algebraically) to convince someone that...

srry i cant upload the image

a)  If it is odd...it will be symmetric with the origin

See that this is so, here :  https://www.desmos.com/calculator/jxqiwmmria

b) If it is odd  we will hve the points  (-x, -y)  and (x , y) on the grpah

So   by a table

x         y

-3      -33

3        33

-2       -12

2         12

-1       -3

1         3

c)   If it is odd      

f(-x) = - f(x)

f(-x) = (-x)^3 + 2(-x)  =   -x^3 - 2x     =  - [ x^2 + 2x ] = - f(x)