TeX джерело:

= \frac{{{a^3} - a{b^2}}}{{ab(a - b)}} = \frac{{a({a^2} - {b^2})}}{{ab(a - b)}} = \frac{{{a^2} - {b^2}}}{{b(a - b)}} = \frac{{(a - b)(a + b)}}{{b(a - b)}} = \frac{{a + b}}{b}