$\left(-5y-4\right)+\left(-7+4\right)$

$\log\left(2x^2+4x\right)$

$\frac{6x+5}{\left(x+9\right)\left(x+7\right)}$

$\frac{d}{dx}cos3x^2$

$\lim_{x\to1}\left(\frac{\ln\left(x\right)-2x+2}{x^4-3x^2+2}\right)$

$\lim_{x\to\infty}\left(\left(\sqrt{2x^2-1}\right)\sqrt{2x^2}\right)$

$7+1-\left(-8\right)$