$-\tan\left(x\right)\cos\left(x\right)=-\sin\left(x\right)$

$\frac{dy}{dx}=\frac{7}{x}+4x,\:y\left(1\right)=-1$

$\lim_{x\to\infty}\sqrt{10x^2-4x^2}-\sqrt{10x^2-6x}$

$3x^2\left(x-y+z\right)$

$4x^2+168x-540$

$-\left(-4+2\right)-\left(4-11-23\right)$

$x\left(4x^2+7\right)$