$x^6+x^8-x^3$

$\frac{dx}{dt}=\frac{1+t}{1-x}$

$\left(x-5\right)\left(x+5\right)-\left(x+2\right)\left(x+8\right)$

$\lim_{x\to0}\left(\frac{9^x-4^x}{x}\right)$

$3ln\left(\left(4e^{3x}\right)^4\left(5e^{\left(50x-4x^2\right)}\right)^2\right)$

$f\left(x\right)=x^4\left(x^9-7\right)$