Question

Chứng minh rằng a/b = c/d nếu:
a+b/c+d = a - b/c-d

Answer 1

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

=>(a+b)(c-d)=(a-b)(c+d)

=>ac-ad+bc-bd=ac+ad-bc-bd

=>-ad+bc=ad-bc

=>-2ad=-2bc

=>ad=bc

=>a/b=c/d