Question

cho a+b/a-b=c+d/c-d.chứng minh a/b=c/d

 

Answer 1

Ta có:
`(a+b)/(a-b) = (c+d)/(c-d)`
`=> (a+b)(c-d)=(a-b)(c+d)`
`=> ac-ad+bc-bd=ac+ad-bc-bd`
`=> 2bc = 2ad`
`=> bc = ad`
`=> c/d = a/b (đpcm)`

 

Answer 2

Ta có:
`(a+b)/(a-b) = (c+d)/(c-d)`
`=> (a+b)(c-d)=(a-b)(c+d)`
`=> ac-ad+bc-bd=ac+ad-bc-bd`
`=> 2bc = 2ad`
`=> bc = ad`
`=> c/d = a/b (đpcm)`