$\left(3x+5\right).\left(4x+6\right)$

$-2^4c$

$\lim_{t\to-1}\left(\frac{\sqrt{1+\tan\left(x\right)}-\sqrt{1+\sin\left(x\right)}}{x^2}\right)$

$\left(a^2b^3+c^5\right)^3$

$\frac{\sec\left(x\right)+\tan\left(x\right)-\sec\left(x\right)-\tan\left(x\right)}{\sec\left(x\right)-\tan\left(x\right)\sec\left(x\right)+\tan\left(x\right)}$

$\frac{d^2}{dy^2}\left(x^2\cdot e^{3xy}+4xz^3\right)$

$\left(\frac{1}{6}x^5\right)\cdot\left(-3x^2\right)\cdot\left(4x^7\right)$