Câu này ta chỉ cần sử dụng tính chất của dãy tỉ số bằng nhau là xong nhé :)
\(\frac{a}{b}=\frac{c}{d}\Rightarrow\frac{3a}{3b}=\frac{3c}{3d}=\frac{a}{b}=\frac{c}{d}\Rightarrow\frac{3a-c}{3b-d}=\frac{a+3c}{b+3d}.\)
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 \(\frac{a}{b}=\frac{c}{d}\), Chứng minh rằng \(\frac{2a-3c}{2b-3d}=\frac{2a+3c}{2a+3d}\)
Cho \(\frac{a}{b}=\frac{c}{d}\), Chứng minh rằng \(\frac{2a-3c}{2b-3d}=\frac{2a+3c}{2a+3d}\)
1. Chứng minh rằng \(\frac{a}{b}\)= \(\frac{c}{d}\)thì \(\frac{a}{b}\)=\(\frac{a+c}{b+d}\)và \(\frac{a}{b}=\)\(\frac{a-c}{b-c}\)
2. Cho \(\frac{a}{b}=\frac{c}{d}\). Chứng minh \(\frac{2a-3c}{2b-3d}=\frac{2a+3c}{2b+3d}\)
1 Cho \(\frac{a}{b}=\frac{c}{d}\)
CMR: b, \(\frac{5a+3b}{5c+3d}=\frac{5a-3a}{5c-3d}\)
\(cho\frac{a}{b}=\frac{c}{d}\)chứng minh rằng\(\frac{a}{b}=\frac{2a+3c}{2a-3c}\)
cho \(\frac{a}{b}=\frac{c}{d}\)chứng minh rằng \(\frac{2a-3c}{2b-3d}\)=\(\frac{2a+3c}{2a+3d}\)
nhanh minh tink minh can gap camr on cac ban
cho \(\frac{a}{b}\)=\(\frac{c}{d}\)CMR \(\frac{2a-3c}{2b-3d}\)=\(\frac{2a+3c}{2a+3d}\)
a, Đặt \(\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=b.k,c=d.k\)
+) \(\frac{5a+3b}{5a-3b}=\frac{5.b.k+3.b}{5.b.k-3.b}=\frac{b.\left(5k+3\right)}{b.\left(5k-3\right)}=\frac{5k+3}{5k-3}\left(1\right)\)
+) \(\frac{5c+3d}{5c-3d}=\frac{5.d.k+3.d}{5.d.k-3.d}=\frac{d.\left(5k+3\right)}{d.\left(5k-3\right)}=\frac{5k+3}{5k-3}\left(2\right)\)
Từ (1) và(2) => ĐPCM
