$x\left(\frac{dy}{dx}\right)-3y=x^4$

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

$x^2+2x+1\cdot x+3$

$\left(x+9\right)\left(x-9\right)-x\left(x+4\right)$

$\int_1^3\frac{1}{x^4\left(x^2-1\right)^{\frac{1}{2}}}dx$

$72y+43y+24u+32y+21u+12u$

$\int\frac{\left(1\right)}{\sqrt{x}}\left(x-4\right)^3dx$