$-\left(-305\right)\:+\:\left(-42\right)\:-\:\left(-7\right)$

$\left(y-z+1\right)\left(-3x\right)$

$-1-3\csc\left(x\right)=-7$

$\ln\left(x-49\right)-ln\left(x+49\right)=-\frac{2}{5}$

$\lim_{x\to\infty}\left(\frac{2^x-5^x}{5^x}\right)$

$3\sin-5\:=\:-2\sin$

$\left(8^{-4}\right)^{-2}$