Question

cho\(\dfrac{a}{b}\)=\(\dfrac{c}{d}\)chứng minh rằng\(\dfrac{5a+3b}{5a-3b}=\dfrac{5c+3d}{5c-3d}\)

Answer 1

\(\dfrac{a}{b}=\dfrac{c}{d}\Rightarrow\dfrac{a}{c}=\dfrac{b}{d}=\dfrac{3b}{3d}=\dfrac{5a}{5c}=\dfrac{5a+3b}{5c+3d}=\dfrac{5a-3b}{5c-3d}\\ \Rightarrow\dfrac{5a+3b}{5a-3b}=\dfrac{5c+3d}{5c-3d}\)