$25a^2+49b^4-9a^2$

$\lim_{x\to6}\left(\frac{\left(x-1\right)}{x^2-7x+6}\right)$

$\lim_{x\to-3}-\frac{\left|x+3\right|}{x+3}$

$\lim_{x\to1}\left(\frac{1-2cos\left(x\right)+\cos\left(2x\right)}{x^2}\right)$

$\left(2ye^{4x}\right)\frac{dy}{dx}=8e^{4x}e^{3y}+3e^{3y}$

$\frac{\sqrt[5]{\sqrt[3]{w^{30}g^{-90}}}}{\sqrt[3]{\sqrt[5]{w^{15}\text{g}^{-120}}}}\cdot\sqrt[15]{-32768}$

$\int_1^4\left(\frac{x}{x^2-4}\right)dx$