Cho \(\frac{a}{b}=\frac{c}{d}\)
a) CMR: \(\frac{5a+5b}{5b}=\frac{c^2+cd}{cd}\)
b) CMR: \(\frac{a^2}{b^2}=\frac{a^2-ac}{b^2-bd}\)
Cho \(\frac{a}{b}=\frac{c}{d}\).Chứng minh:\(\frac{a^2}{b^2}=\frac{5a^2+2c^2}{5b^2+2d^2}\)
Cho:
\(\frac{a}{b}=\frac{c}{d}\left(b\ne d\right)\)
Chứng minh a/
\(\frac{\left(a-c\right)^4}{\left(b-d\right)^4}=\frac{5a^4+7c^4}{5b^4+7d^4}\)
b/
\(\frac{ac}{bd}=\frac{5a^2+7c^2}{5b^2+7d^2}\)
CMR Nếu \(\frac{a}{b}=\frac{c}{d}\)thì:
a)\(\left(\frac{a-b}{c-d}\right)^4=\frac{a^4+b^4}{c^4+d^4}\)
b)\(\frac{5a+3b}{5a-3b}=\frac{5c+3d}{5c-3d}\)
c)\(\frac{7a^2+3ab}{11a^2-8b^2}=\frac{7c^2+3cd}{11c^2-8d^2}\)
1 a) 2a=3b:5b=7c và 3a +5c-7b=30
b)\(\frac{x-1}{2}=\frac{x+3}{4}=\frac{z-5}{6}\)và 5z-3x-4y=50
c)3x=4y=6z và x-3y+2z=70
d)\(\frac{6}{11}x=\frac{9}{2}y=\frac{18}{5}z\)và x+y+z=20
2 cho \(\frac{a}{b}=\frac{c}{d}\)và a;b;c;d\(\ne\)0
a)\(\frac{a}{a-b}\frac{c}{d}\)
b)\(\frac{ac}{bd}=\frac{a^2+c^2}{b^2+d^2}\)
c)\(\frac{a}{3a+b}=\frac{c}{3c+d}\)
d)\(\frac{a^2-b^2}{c^2-d^2}=\frac{ab}{cd}\)
g)\(\frac{5a+3b}{5c+3b}=\frac{5a-3b}{5c-3d}\)
h)\(\frac{2a+3b}{2a-3d}=\frac{2c+3d}{2c-3d}\)
Cho tỷ lệ thức:\(\frac{a}{b}\)=\(\frac{c}{d}\)(b, d khác 0). Chứng minh rằng:
\(\frac{a-b}{b}\)= \(\frac{c-d}{d}\) b) \(\frac{ab}{cd}\)= \(\frac{\left(a+b\right)}{\left(c+d\right)^2}^2\)
c) \(\frac{3c^2+5a^2}{3d^2+5b^2}\)= \(\frac{c^2}{d^2}\)
Cho : \(\frac{a}{b}=\frac{c}{d}CMR:\)\(\frac{ab}{cd}=\frac{a^2-b^2}{c^2-d^2}v\text{à}\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)
\(Cho\frac{a}{b}=\frac{c}{d}.CMR:\frac{5a^2+7ab}{4a^2-9b^2}=\frac{5c^2+7cd}{4c^2-9cd}\)
cho \(\frac{a}{b}\)=\(\frac{c}{d}\)cmr:\(\frac{4a^4+5b^4}{4c^4+5d^4}\)= \(\frac{a^2.b^2}{c^2.d^2}\)