$x\frac{dy}{dx}+3y=4x^2-3x$

$cos\left(x-\frac{5\pi}{4}\right)=-\frac{\sqrt{2}}{2}\left(cosx+sinx\right)$

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

$6a^4-7a^4+9a^4+7a^4+8a^4-9a^4+4a^4$

$15\le x+2$

$3xy+121\cdot3xy-121$

$\left(5x+y\right)+\left(5x-y\right)$