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

$\int\left(3\sin\left(5x\right)\cos\left(4x\right)\right)dx$

$\int\frac{2}{\sqrt{3+2x}}dx$

$\int\frac{65}{\left(x+9\right)\left(x-3\right)}dx$

$3a+4c+9c-7b-7a-15c$

$x^2+7x+12\ge0$

$20-25+14\left(-3\right)$