$y ^ { 2 } = \frac { x - 1 } { x + 1 }$

$a+a+3b+b$

$\lim_{x\to infinity}\left(\sqrt[3]{x^3-9x^2}-x\right)$

$\frac{\left(6x^4+11x^3+13x^2+13x+2\right)}{3x^3+x^2+4x}$

$\lim_{x\to3}\:\left(2x-6\right)\left(x^2-9\right)$

$17x+13+32-2x$

$\lim_{x\to-5}\left(\frac{x^2+12x+35}{-63-2x+x^2}\right)$