Question

giúp mik vs

Answer 1

\(\dfrac{21a+10b}{a-11b}=\dfrac{21c+10d}{c-11d}\Rightarrow\dfrac{21a+10b}{a-11b}-21=\dfrac{21c+10d}{c-11d}-21\)

\(\Rightarrow\dfrac{241b}{a-11b}=\dfrac{241d}{c-11d}\Rightarrow\dfrac{b}{a-11b}=\dfrac{d}{c-11d}\)

\(\Rightarrow\dfrac{a-11b}{b}=\dfrac{c-11d}{d}\)

\(\Rightarrow\dfrac{a}{b}-11=\dfrac{c}{d}-11\)

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