So sánh:
a) 39/47 và 43/51 b) 311/31 và 211/21 c) 1530/1632 và 1414/1515 d)-373737/515151 và -1111/1212
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a. \(\frac{26}{42}< \frac{56}{78}\)
b.\(\frac{58}{89}< \frac{36}{53}\)
c.\(\frac{1530}{1632}>\frac{1414}{1515}\)
d.\(\frac{-373737}{515151}>\frac{-1111}{1212}\)
k cho mk nha!!!!
a) \(\dfrac{12}{14}=\dfrac{1200}{1400}=\dfrac{1400-200}{1400}=1-\dfrac{200}{1400}\)
\(\dfrac{1212}{1414}=\dfrac{1414-200}{1414}=1-\dfrac{200}{1414}\)
vì \(\dfrac{200}{1414}< \dfrac{200}{1400}\)
Nên \(1-\dfrac{200}{1400}< 1-\dfrac{200}{1414}\)
Vậy \(\dfrac{12}{14}< \dfrac{1212}{1414}\)
Các bài sau tương tự
\(\frac{2323+1313+1414+1515+1616}{4141+2222+2323+2424+2525}\)
=\(\frac{8181}{13635}\)
\(\dfrac{1111}{1212}\) và \(\dfrac{1515}{1616}\)
\(\dfrac{1111}{1212}=\dfrac{1111\times1616}{1212\times1616}=\dfrac{1795376}{1958592}\)
\(\dfrac{1515}{1616}=\dfrac{1515\times1212}{1616\times1212}=\dfrac{1836180}{1958592}\)
Vì: 1836180 > 1795376
=> \(\dfrac{1111}{1212}< \dfrac{1515}{1616}\)
\(\dfrac{1111}{1212}\) = \(\dfrac{1111:101}{1212:101}\) = \(\dfrac{11}{12}\)= 1 - \(\dfrac{1}{12}\) ; \(\dfrac{1515}{1616}\) =\(\dfrac{1515:101}{1616:101}\) = \(\dfrac{15}{16}\) = 1 -\(\dfrac{1}{16}\)
Vì \(\dfrac{1}{12}\) > \(\dfrac{1}{16}\) nên \(\dfrac{1111}{1212}\) < \(\dfrac{1515}{1616}\)
\(\frac{1010+1111+1212+1313+1414+1515}{2020+2121+2222+2323+2424+2525}=\frac{10\times101+11\times101+12\times101+13\times101+14\times101+15\times101}{20\times101+21\times101+22\times101+23\times101+24\times101+25\times101}=\frac{101\times\left(10+11+12+13+14+15\right)}{101\times\left(20+21+22+23+24+25\right)}\)
\(=\frac{10+11+12+13+14+15}{20+21+22+23+24+25}=\frac{75}{135}=\frac{5}{9}\)
1010+1111+1212+1313+1414+1515= 7575
2020+2121+2222+2323+2424+2525= 13635