$\int\frac{2x+3}{9-4x}dx$

$\left(11x^2-6y^2-5\cdot\left(-\frac{1}{3}\cdot x+\frac{13}{9}\cdot y+13\right)^2\right)\cdot39$

$2t^2+1+4t$

$\sin\left(2\right)x=-9\cos\left(x\right)$

$\left(-5c+d\right)^2$

$a+b\left(\sqrt{a^6}-b^6\right)$

$f\left(x\right)=\frac{senx}{cosx}$