Question

cho a/b=c/d chứng minh rang a) a/b = a+c/b+d

b) a+b/c+d = a-b/c-d

c) a^2/b^2 = ac/bd

Answer 1

b)  \(ad=bc\)

\(\Rightarrow ac-ad+bc-bd=ac-bc+ad-bd\)

\(\Rightarrow a.\left(c-d\right)+b.\left(c-d\right)=c.\left(a-b\right)+d.\left(a-b\right)\)

\(\Rightarrow\left(a+b\right)\left(c-d\right)=\left(c+d\right)\left(a-b\right)\)

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

Answer 2

ai giai gium minh ma cinh xac nhat minh cho

Answer 3

nhưng mà cho cái gì????????????

Answer 4

a)  \(\frac{a}{b}=\frac{c}{d}\Rightarrow ad=bc\)

     \(\Rightarrow ad+ab=bc+ab\)

     \(\Rightarrow a.\left(b+d\right)=b.\left(c+a\right)\)

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

b)