$\left(-1\right)^{-8}$

$\frac{4x}{5x+1\right)\left(x+4\right)}-\frac{3x}{\left(5x+1\right)\left(x-3\right)}$

$\frac{x^5+x^4-2x+3}{x-1}$

$49\left(x+2\right)^2-16\left(2x-3\right)^2$

$1.5-3r+8r+2.5r$

$m^6m^6-21-54$

$2\cdot\left[3+\left(-2\right)\cdot5\right]+\left(-2\right)\cdot\left(-5\right)\cdot\left(-3\right)$