$\left(k-7\right)\left(-4k-3\right)$

$\left(1+sina\right)\left(1-sina\right)+cos^2a$

$\frac{dy}{dx}+\frac{2}{x}+x^2=sen2x$

$200-\left|3+2\left(4-1^5\right)-2\right|$

$\frac{dy}{dx}=y\tan\left(x\right)+\frac{2x}{\cos\left(x\right)}$

$36x^4+72x^2y^2+81y^4$

$6x^5y^2=4x$