Đáp án:
Giải thích các bước giải:
$\frac{a^2 - 2a +1}{a^2 - a}$ - $\frac{2a^3 - a^2}{a^4 + a^3}$
=$\frac{(a-1)^2}{a(a-1)}$ - $\frac{(a^2)(2a-1)}{(a^3)(a+1)}$
=$\frac{a-1}{a}$ - $\frac{2a-1}{a(a+1)}$
=$\frac{(a-1)(a+1)}{a(a+1)}$- $\frac{2a-1}{a(a+1)}$
=$\frac{(a^2)-1}{a(a+1)}$ - $\frac{2a-1}{a(a+1)}$
=$\frac{(a^2)-1 -2a +1}{a(a+1)}$
=$\frac{(a^2) -2a}{a(a+1)}$
=$\frac{a(a-2)}{a(a+1)}$
=$\frac{a-2}{a+1}$
=$\frac{a+1-2-1}{a+1}$
=$\frac{a+1-3}{a+1}$
=$\frac{a+1}{a+1}$ - $\frac{3}{a+1}$
=1-$\frac{3}{a+1}$
