Question

[Xin chào]

cho a/b =b/c=c/d=d/a trong đó a+b+c+D khác o 

tính A= 2a-b/c+d +2b-c/d+a +2c-d/a+b + 2d-a/b+c

Answer 1

[Dich Duong Thien Ty]

Ta co : 

a/b = b/c = c/d = d/a = (a+b+c+d)/(b+c+d+a) = 1

=> a = b = c = d

A = (2a-b)/(c+d) + (2b-c)/(d+a) + (2c-d)/(a+b) + (2d-a)/(b+c)

= a/2a + a/2a + a/2a + a/2a = 1/2 + 1/2 + 1/2 + 1/2

= 2

Vậy.......................

nho**** nhe thanks