$9z^4+42z^2+49$

$\left(\frac{1}{2}x+y^3\right)^5$

$-\left(6a^3+9a^4+7a-12-5a^2\right)+\left(3-3a^4+2a^4-8a\right)$

$\left(6x^2\right)^2-2\left(6x^2\right)\left(\frac{1}{2}xy\right)^2+\left(\frac{1}{2}xy\right)^2$

$\frac{dy}{dx}=\sqrt{x^4}+2$

$\frac{d}{dx}\left(y=\sqrt{x}\right)$

$-6+0+-1+-3$