$\left(x+14\right)\left(x+9\right)$

$1-253$

$\frac{\left(t^2+1\right)dy}{dt}=2y$

$\ln\left(e^{x+2}\right)=4$

$\frac{d^2}{dx^2}\left(9\sin\left(x\right)\cdot\cos\left(x\right)\right)$

$21:\left(-7\right)+10\cdot\left(-2\right)+9\cdot4-15\cdot3$

$\lim_{x\to1}\left(\frac{x-1}{sin\left(x\right)}\right)$