finding horizontal tangent line

Uh I meant a point on the graph. Answer is (2,-8).. I figured it out. but thank you, I do need to graph it later on.

may be you mean that:

https://www.desmos.com/calculator/lzpj7xzdvq

Are you doing CALCULUS?

if   so   f'(x) is the slope of the graph at any point

f'(x) = 6x-12     A 'HORIZONTAL' line has slope = 0    so   6x-12= 0    gives x=2 then substitute into the original equation to get 'y'   3(2^2) -12(2)+4 = -8    gives   2,-8   as the POINT where the HORIZONTAL line  y= -8  intersects the graph