Đáp án:
$\frac{3}{2.3}$ + $\frac{3}{3.4}$ + $\frac{3}{3.5}$ +...+ $\frac{3}{96.97}$ = $\frac{285}{194}$
Giải thích các bước giải:
$\frac{3}{2.3}$ + $\frac{3}{3.4}$ + $\frac{3}{3.5}$ +...+ $\frac{3}{96.97}$
= 3.($\frac{1}{2.3}$ + $\frac{1}{3.4}$ + $\frac{1}{4.5}$ +...+ $\frac{1}{96.97}$ )
= 3.($\frac{1}{2}$ - $\frac{1}{3}$ + $\frac{1}{3}$ - $\frac{1}{4}$ + $\frac{1}{4}$ - $\frac{1}{5}$ +...+ $\frac{1}{96}$ - $\frac{1}{97}$
= 3.( $\frac{1}{2}$ - $\frac{1}{97}$ )
= 3.$\frac{95}{194}$
= $\frac{285}{194}$
