# How do you find the derivative of the function y=3x(6x-5x^2)?

1) multiply by $3 x$ to get:
$y = 18 {x}^{2} - 15 {x}^{3}$ and derive:
$y ' = 36 x - 45 {x}^{2}$
$y ' = 3 \left(6 x - 5 {x}^{2}\right) + 3 x \left(6 - 10 x\right) =$
$= 18 x - 15 {x}^{2} + 18 x - 30 {x}^{2} = 36 x - 45 {x}^{2}$