Question 551131
4x^3
.
4*4=16
4*3=12
and 
x^3*x=x^4
x^3
.
{{{16x^4 - 12x^3}}}
{{{(4*4*x^3x) - (4*3x^3)}}}
{{{(highlight(4)*4*highlight(x^3)x) - (highlight(4)*3highlight(x^3))}}}
{{{4x^3(4x-3)}}}