$4x^4+1=0$

$2b-4a=17$

$\lim_{x\to\infty}\left(e^{\left(x^4-x\right)}\right)$

$4\cos^26x-2=0$

$45\cdot11$

$\frac{d}{dx}\left(\frac{\left(\left(x+1\right)\left(5x+1\right)\left(7x+1\right)\right)}{\sqrt{8x+1}}\right)$

$\lim_{n\to\infty}\left(\left(1+\frac{1}{2n+1}\right)^{n^{2}+2}\right)$