Answer
$f'(x)=6.3x^2$
Work Step by Step
First you have to re-write this number before you can take its derivative. You re-write it as $2.1x^{3}$ Then you take the derivative of that number by applying the derivative rule. A number with an x variable, you take the exponent, multiply it with the number in front, then subtract one from the exponent. And any number without an x variable is changed to 0.