$\frac{\cot\left(x\right)}{1+csc\:x}=-\frac{csc\:x}{1+csc\:x}$

$\left(-924\right)-\left(49\right)$

$sinasinb=0.5\left[cos\left(a-b\right)-cos\left(a+b\right)\right]$

$3\cdot3^2+5\cdot\left(-1\right)-1$

$\left(4x^2-9\right)\left(4x^2-6\right)$

$7x+5x+4x-12;\:x=-12$

$\left(\frac{5d^5}{6d}\right)^2$