TeX Quellcode:
\dfrac{\left(9a-5b\right)^2}{\left(81a^2-90ab+25b^2\right)^2} = \dfrac{\left(9a-5b\right)^2}{\left(\left(9a-5b\right)^2\right)^2} = \dfrac{\left(9a-5b\right)^2}{\left(9a-5b\right)^4} = \dfrac{1}{\left(9a-5b\right)^2}