Question

Tổng \(\frac{a}{b}+\frac{_{-a}}{b+1}\)bằng bao nhiêu ?

Answer 1

\(\frac{a}{b}+\frac{-a}{b+1}=\frac{a\left(b+1\right)}{b\left(b+1\right)}+\frac{-ab}{b\left(b+1\right)}=\frac{ab+a}{b\left(b+1\right)}+\frac{-ab}{b\left(b+1\right)}=\frac{a}{b\left(b+1\right)}\)

Answer 2

\(\frac{a}{b}+\frac{-a}{b+1}=\frac{a\left(b+1\right)}{b\left(b+1\right)}+\frac{-ab}{b\left(b+1\right)}=\frac{ab+a-ab}{b\left(b+1\right)}=\frac{a}{b\left(b+1\right)}\)