Question

so xánh các số hửu tỉ sau :

a) \(\dfrac{456}{23}\)và\(\dfrac{465}{32}\)     b) \(-\dfrac{173}{457}\)và\(\dfrac{-16}{47}\)

Answer 1

\(a,\dfrac{456}{23}=\dfrac{456.32}{23.32}=\dfrac{14592}{736}\)
\(\dfrac{465}{32}=\dfrac{465.23}{32.23}=\dfrac{10695}{736}\)
Vì \(14592>10695\) nên \(\dfrac{14592}{736}>\dfrac{10695}{736}\)
hay \(\dfrac{456}{23}>\dfrac{465}{32}\)
\(b,\dfrac{-173}{457}=\dfrac{\left(-173\right).47}{457.47}=\dfrac{-8131}{21479}\)
\(\dfrac{-16}{47}=\dfrac{\left(-16\right).457}{47.457}=\dfrac{-7312}{21479}\)
Vì \(8131>7312\) nên \(\dfrac{-8131}{21479}< \dfrac{-7312}{21479}\)
hay \(\dfrac{-173}{457}< \dfrac{-16}{47}\)