# How do you multiply 4x(3x^2+2x+1) ?

 = color(blue)( 12x^3 + 8x^2 +4x
$\textcolor{b l u e}{4 x} \left(3 {x}^{2} + 2 x + 1\right)$
Here $\textcolor{b l u e}{4 x}$ needs to be multiplied with each term within bracket:
$= \textcolor{b l u e}{4 x} . \left(3 {x}^{2}\right) + \textcolor{b l u e}{4 x} . \left(2 x\right) + \textcolor{b l u e}{4 x} . \left(1\right)$
 = color(blue)( 12x^3 + 8x^2 +4x