Question

cho a,b,n thuộc N* .Hãy so sánh

\(\frac{a+n}{b+n}\) và \(\frac{a}{b}\)

 

Answer 1

a+n / b+ n > a/b 

mik k bt bn k cho mik nha

Answer 2

Với a,b,n\(\in\)N* thì:

 +,Nếu a>b thì \(\frac{a+n}{b+n}< \frac{a}{b}\Leftrightarrow b\left(a+n\right)< a\left(b+n\right)\Leftrightarrow ba+bn< ab+an\Rightarrow bn< an\Rightarrow b< a\)(đúng)

 +,Nếu a<b thì \(\frac{a+n}{b+n}>\frac{a}{b}\Leftrightarrow b\left(a+n\right)>a\left(b+n\right)\Leftrightarrow ba+bn>ab+an\Leftrightarrow bn>an\Rightarrow b>a\)(đúng)

Vậy............