$144 \times 4 ^ { 4 } - 819 ^ { 4 } b ^ { 2 }$

$9x^2-\left(y+4\right)^2$

$\left(x-7\right)^5$

$\left(\sin\left(x\right)-\cos\left(x\right)\right)\left(\sin\left(x\right)+\cos\left(x\right)+2\cos^2\left(x\right)\right)$

$-\frac{4}{5}\:x\:2\:\frac{1}{9}$

$\frac{4s-9}{\left(s-1\right)\left(s-2\right)\left(s+3\right)}$

$\frac{x^3+2x^2-1}{x^3+1}$