Question

Cho tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh \(\dfrac{a-b}{b}=\dfrac{c-d}{d}\)

Answer 1

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

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

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