Question

[Tiffany Ho]

CMR: nếu \(\frac{AB}{CD}\)=\(\frac{MN}{PQ}\)thì \(\frac{AB+CD}{CD}\)=\(\frac{MN+PQ}{PQ}\):\(\frac{AB-CD}{CD}\)=\(\frac{MN-PQ}{PQ}\)

Answer 1

[Nguyễn Bảo Long]

do AB/CD=MN/PQ => AB.PQ=MN.CD

TA CÓ: AB.PQ=MN.CD=>AB.PQ+CD.PQ=MN.CD+CD.PQ=>PQ(AB+CD)=CD(MN+PQ)=>AB+CD/CD=MN+PQ/PQ

TA CÓ: AB.PQ=MN.CD=>AB.PQ-CD.PQ=MN.CD-CD.PQ=>PQ(AB-CD)=CD(MN-PQ)=>AB-CD/CD=MN-PQ/PQ

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