a, \(\frac{a}{b}=\frac{c}{d}\Rightarrow\frac{a}{c}=\frac{b}{d}=\frac{2a}{2c}=\frac{5b}{5d}=\frac{2a+5b}{2c+5d}\left(1\right)\)
Lại có: \(\frac{a}{c}=\frac{b}{d}=\frac{3a}{3c}=\frac{7b}{7d}=\frac{3a-7b}{3c-7d}\left(2\right)\)
Từ (1) và (2) => \(\frac{2a+5b}{2c+5d}=\frac{3a-7b}{3c-7d}\Rightarrow\frac{2a+5b}{3a-7b}=\frac{2c+5d}{3c-7d}\)
Câu b tương tự
cho ti le thuc \(\frac{a}{b}=\frac{c}{d}\)chung minh:
\(\frac{5a+2c}{5b+2d}=\frac{a-4c}{b-4d}\)
Cho \(\frac{a}{b}=\frac{c}{d}\) Chung minh cac ti le thuc sau :
a) \(\frac{2a+c}{2b+d}=\frac{2a-c}{2b-d}\)
b) \(\frac{2a+3c}{a}=\frac{2b+3d}{b}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)
\(\frac{a+b}{b}=\frac{c+d}{d}\)
\(\frac{a+c}{b+d}=\frac{a-c}{b-d}\)
\(\frac{3a+5b}{2a-7b}=\frac{3c+5d}{2c-7d}\)
cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}\).chứng minh
a)\(\frac{3a+5b}{3a-5b}=\frac{3c+5d}{3c-5d}\)
b) \(\frac{2a+3b}{2a-3b}\)=\(\frac{2c+3d}{2c-3d}\)
cho ti le thuc \(\frac{a}{b}=\frac{c}{d}\) chung minh rang \(\frac{a+b}{a-b}=\frac{c+d}{c-d}\)
cho ti le thuc \(\frac{a}{b}\)=\(\frac{c}{d}\)
chung minh rang\(\frac{a}{b}\)=\(\frac{7a+5c}{7b+5d}\)[b+d khac 0]
cac ban co biet tai sao minh go dau cac chu cai thi chu cai do va dau deu bien mat khong? giup minh voi , cau hoi tren la 1 vi du
Cho \(\frac{a}{b}=\frac{c}{d}\)Chứng minh \(\frac{3a+7b}{3a-5b}=\frac{3c+7d}{3c-5d}\)
cho ti le thuc \(\frac{a}{c}=\frac{a}{d}\)Chung to rang \(\frac{a}{b+c}=\frac{a}{b+d}\)
cho ti le thuc \(\frac{a}{b}=\frac{c}{d}\). CMR : \(\frac{4a+6b}{5a-7b}=\frac{4c+6d}{5c-7d}\)
