So sánh:
13/40 và 7/15
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 1:
\(\dfrac{-5}{18}=\dfrac{-20}{72};\dfrac{7}{-24}=\dfrac{-21}{72}.\)
\(\dfrac{-15}{-40}=\dfrac{3}{8}=\dfrac{9}{24};\dfrac{24}{-72}=\dfrac{-1}{3}=\dfrac{-8}{24}.\)
Bài 3:
a) \(\dfrac{2}{3}h=\dfrac{8}{12}h;\dfrac{3}{4}h=\dfrac{9}{12}h.\Rightarrow\dfrac{2}{3}h< \dfrac{3}{4}h.\)
b) \(\dfrac{4}{5}km/h=\dfrac{8}{10}km/h;\dfrac{9}{10}km/h.\Rightarrow\dfrac{4}{5}km/h< \dfrac{9}{10}km/h.\)
21/35=3/5; 12/20=3/5
=>21/35=12/20
24/35<1<21/7
35/49=5/7; 40/64=5/8
=>35/49>40/64
2424/4848=1/2
9/11=1-2/11
13/15=1-2/15
mà 2/11>2/15
nên 9/11<13/15
19/15>11/15
a) \(\dfrac{7}{12}< \dfrac{7+1}{12+1}< \dfrac{78}{13}\Rightarrow\dfrac{7}{12}< \dfrac{8}{13}\)
b) \(-4,25=-\dfrac{425}{100}=-\dfrac{17}{4}=-\dfrac{34}{8}< -\dfrac{28}{8}\Rightarrow-4,25< -\dfrac{28}{8}\)
c) \(-0,33>-0,5=-\dfrac{1}{2}=-\dfrac{19}{38}\Rightarrow-0,33>-\dfrac{19}{38}\)
d) \(\dfrac{11}{13}< \dfrac{11+2}{13+2}=\dfrac{13}{15}\Rightarrow\dfrac{11}{13}< \dfrac{13}{15}\Rightarrow-\dfrac{11}{13}>-\dfrac{13}{15}\)
\(a\)\(3^{39}\)và \(11^{21}\)
\(3^{39}< 11^{21}\)vì
\(3^{39}< 3^{40}=3^{39}< \left(3^2\right)^{20}=9^{20}< 11^{21}\)
\(\Rightarrow3^{39}< 11^{29}\)
a, 339 < 340 = (32)20=920<1121
b, chép đúng đề bài ko pn
c, 1340< 1640= (24)40= 2160<2162
13/40>1; 7/15>1
vay suy ra 13/40>7/15
\(\frac{13}{40}va\frac{7}{15}\)\(=\)\(\frac{195}{600}va\frac{280}{600}\)vậy\(\frac{13}{40}< \frac{7}{15}\)