ủa

Ta có: \(\dfrac{a}{b}=\dfrac{c}{d}\)

\(\Rightarrow\text{ }\dfrac{b}{a}=\dfrac{d}{c}\)

\(\Rightarrow\text{ }\dfrac{b}{a}+1=\dfrac{d}{c}+1\)

\(\Rightarrow\text{ }\dfrac{b+a}{a}=\dfrac{d+c}{c}\)

\(\Leftrightarrow\text{ }\dfrac{a+b}{a}=\dfrac{c+d}{c}\) (đpcm)

Thiếu dữ kiện hay sao ý ạ?