Question

so xánh các số hửu tỉ sau :

a) \(\dfrac{47}{39}\)và\(\dfrac{65}{73}\)      b) \(\dfrac{-33}{37}\)và\(\dfrac{-34}{35}\)     c) \(\dfrac{29}{59}\)và\(\dfrac{47}{93}\)

Answer 1

\(a,\dfrac{47}{39}=\dfrac{47.73}{39.73}=\dfrac{3431}{2847}\)
\(\dfrac{65}{73}=\dfrac{65.39}{73.39}=\dfrac{2535}{2847}\)
Vì \(3431>2535\) hay \(\dfrac{3431}{2847}>\dfrac{2535}{2847}\)
hay \(\dfrac{47}{39}>\dfrac{65}{73}\)
\(b,\dfrac{-33}{37}=\dfrac{\left(-33\right).35}{37.35}=\dfrac{-1155}{1295}\)
\(\dfrac{-34}{35}=\dfrac{\left(-34\right).37}{35.37}=\dfrac{-1258}{1295}\)
Vì \(1155< 1258\) nên \(\dfrac{-1155}{1295}>\dfrac{-1258}{1295}\)
hay \(\dfrac{-33}{37}>\dfrac{-34}{35}\)
\(c,\dfrac{29}{59}=\dfrac{29.93}{59.93}=\dfrac{2697}{5487}\)
\(\dfrac{47}{93}=\dfrac{47.59}{93.59}=\dfrac{2773}{5487}\)
Vì \(2697< 2773\) nên \(\dfrac{2697}{5487}< \dfrac{2773}{5487}\)
hay \(\dfrac{29}{59}< \dfrac{47}{93}\)

Answer 2

a)

Do 39 < 73

b)

Do -1155 > -1258

c)

Do 2697 < 2773