$16x^{2-40x+25}$

$\frac{\left(-1\right)^k\left(k+6\right)}{k^2+4k+1}$

$y=\frac{\left(z^2-5\right)^3}{\left(z+4\right)^2}$

$-4a+3a+2a$

$\left(6x^2+8x^6\right)^2\left(4x^2-6\right)^2$

$\lim_{x\to\infty}\arccos\left(\frac{1+e^{2x}}{1+2e^{2x}}\right)$

$\left(10x+3y-8\right)-\left(17x-40y+1\right)$