Question 951473
{{{ T(x) = x^4+2x^3}}} ...to find the factors or x-intercepts, first set {{{ T(x) =0}}} 

{{{  x^4+2x^3=0}}}

{{{ x^3( x+2)=0}}}

x-intercepts:

if {{{ x^3=0}}}, then we have three same solutions {{{x=0}}}

if {{{ ( x+2)=0}}} then {{{x=-2}}}

to graph it, make a table:

{{{x}}}|{{{T(x)}}}
{{{-3}}}|{{{25}}}......{{{ T(-3) = (-3)^4+2(-3)^3=81-56=25}}}
{{{-2}}}|{{{0}}}
{{{-1}}}|{{{-1}}}......{{{ T(-1) = (-1)^4+2(-1)^3=1-2=-1}}}
{{{0}}}|{{{0}}}
{{{1}}}|{{{3}}}......{{{ T(1) = 1^4+2(1)^3=1+2=3}}}
{{{2}}}|{{{32}}}......{{{ T(2) = 2^4+2(2)^3=16+16=32}}}

plot all points and draw a line through

{{{drawing( 600, 600, -5,5, -5, 50, 
circle(0,0,.1),circle(-2,0,.1),circle(-1,-1,.1),circle(1,3,.1),circle(2,32,.1),circle(-3,25,.1),
locate(0,0,p(0,0)),locate(-2,0,p(-2,0)),locate(-1,-1,p(-1,-1)),
locate(1,3,p(1,3)),locate(2,32,p(2,32)),locate(-3,25,p(-3,25)),

graph( 600, 600, -5,5, -5, 50, x^4+2x^3)) }}}