Cho a+b+c+d ≠ 0 và \(\dfrac{a}{b+c+d}=\dfrac{b}{a+c+d}=\dfrac{c}{b+a+d}=\dfrac{d}{c+b+a}\)

Tính giá trị biểu thức:

P = \(\dfrac{2a+5b}{3c+4d}-\dfrac{2b+5c}{3d+4a}+\dfrac{2c+5d}{3a+4b}+\dfrac{2d+5a}{3c+4b}\)

Cho a+b+c+d ≠ 0 thỏa mãn: 
\(\dfrac{a}{b+c+d}=\dfrac{b}{a+c+d}=\dfrac{c}{b+a+d}=\dfrac{d}{c+b+a}\)

Tính P = \(\dfrac{2a+5b}{3c+4d}+\dfrac{2b+5c}{3d+4a}+\dfrac{2c+5d}{3a+4b}+\dfrac{2d+5a}{3c+4b}\)

a/b+c+d=b/a+c+d=c/b+a+d=d/c+b+a

P=2a+5b/3c+4d-2b+5c/3d+4a-2c+5d/3a+4b+2d+5a/3c+4b

cho \(\frac{a}{b}=\frac{c}{d}\left(a,b,c,d\ne0\right)\)và đôi 1 khác nhau , khác đôi nhau .

Chứng minh rằng :

a, \(\frac{a-b}{a+b}=\frac{c-d}{c+d}\)

b, \(\frac{2a+5b}{3a-4b}=\frac{2c-5d}{3c-4d}\)

Cho a , b ,c ,d thỏa mãn : \(\frac{a}{a+2b}=\frac{c}{c+2d}\). Tính \(\frac{a^2d^2-4b^2c^2}{abcd}\)

Cho a ,b ,c , d thỏa mãn : \(\frac{2a+3c}{2b+3d}=\frac{3a-4c}{3b-4d}\).. Tính \(\frac{4a^3d^3-b^3c^3}{4b^3c^3-a^3d^3}\)

Cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}\)

a,\(\frac{a-b}{a+b}=\frac{c-d}{c+d};\)

b,\(\frac{2a+5b}{3a-4b}=\frac{2c+5d}{3c-4d};\)

c,\(\frac{ab}{cd}=\frac{\left(a-b\right)^2}{\left(c-d\right)^2};\)

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 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 \(\frac{2a+5b}{3a-4b}=\frac{2c+5d}{3c-4d}\)