$\left(5x+4b\right)\left(x-2b\right)$

$8+x^2-4x^3+5x^2$

$\log\left(x+4\right)-\log\left(x-5\right)=\log\left(2\right)$

$-10\sqrt{a^2b}+14\sqrt{ba^2}-7\sqrt{a^2b}+\sqrt{ba^2}$

$\frac{x'}{x}=\frac{t}{\left(t^2+4\right)}$

$\left(\frac{1}{2}+ab\right)\left(\frac{1}{2}-ab\right)-\left(a^2b^2-\frac{3}{4}\right)$

$\frac{4x^2+16x+16}{x+2}$