Chain rule.
or rewrite as $y = 6^{20}x^{20}$ and use the Power Rule.

Recall that the derivative of $y =\operatorname{tan}x$ is $y^\prime =\operatorname{sec}^2x$..

Do you see the pattern?
Notice that all three of these problems ask you to differentiate composite functions with an 'inner' function that has a coefficient of $6$.
Compare and contrast their derivatives.