Question 293989
Pick an x, plug it in and plot that point. 
Example: {{{x=1}}}
{{{f(1)=1^3-1^2-12=1-1-12=-10}}}
Plot (1,-10).
{{{x=0}}}
{{{f(0)=0-0-12=-12}}}
The more points, the better the graph definition. 
The higher the power of x, the more points you need. 
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{{{ graph( 300, 300, -5, 5, -20, 20, x^3-x^2-12x) }}}