$y=\frac{1}{x+1}-\log\left(x+1\right)$

$( x y ^ { 2 } + 3 x ^ { 3 } y ) ^ { 2 }$

$5.9\cdot21$

$a^6-10a^3x^3+25x^6$

$\int_0^{\infty}\left(\frac{\sqrt{x}}{3^x}\right)dx$

$\int\frac{1}{2x\sqrt{1-x^2}^1}dx$

$\log\left(3\right)+\log\left(x-1\right)=\log\left(2\right)+\log\left(x+1\right)$