Answer
$4x+3-\frac{10}{3x}$
Work Step by Step
As we are given that $(12x^4+9x^3-10x^2)\div \frac{1}{3x^3}$
Write: $(x^2+2x)=x(x+2)$
Thus, $(12x^4+9x^3-10x^2)\div \frac{1}{3x^3}=\dfrac{(12x^4+9x^3-10x^2)}{3x^3}$
$=\dfrac{12x^4}{3x^3}+\dfrac{9x^3}{3x^3}-\dfrac{10x^2}{3x^3}$
$=4x+3-\frac{10}{3x}$
