$\tan\left(4x+y\right)=a$

$\int_{-\pi}^0x\sqrt{x^2+a^2}dx$

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

$\lim_{x\to\frac{\pi}{4}}\left(25x\right)$

$\int\frac{1}{\sec\left(x\right)\left(1+cos\left(m\right)\right)}dx$

$4x^2-10$

$\sqrt{\frac{72x^2}{8x^2\cdot y^7}}$