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a) \(\dfrac{8}{9}< 1;\dfrac{13}{7}>1\Rightarrow\dfrac{8}{9}< \dfrac{13}{7}\)
b) \(\dfrac{16}{27}>\dfrac{15}{27}>\dfrac{15}{29}\Rightarrow\dfrac{16}{27}>\dfrac{15}{29}\)
1.a) 3/4 > 5/10
b) 35/25 > 16/14
2.a) 7/5 > 5/7
b) 14/16 < 24/21
HT nha
( bạn t.i.c.k cho mik nha, mik cảm ơn )
a) \(\dfrac{6}{14}=\dfrac{6:2}{14:2}=\dfrac{3}{7}\)
\(\dfrac{3}{7}< \dfrac{4}{7}\)
b) \(\dfrac{6}{15}=\dfrac{6:3}{15:3}=\dfrac{2}{5}\)
\(\dfrac{3}{5}>\dfrac{2}{5}\)
c) \(\dfrac{10}{18}=\dfrac{10:2}{18:2}=\dfrac{5}{9}\)
\(\dfrac{5}{9}>\dfrac{2}{9}\)
\(a,MSC:4\\ \dfrac{1}{2}=\dfrac{1\times2}{2\times2}=\dfrac{2}{4}\)
\(\dfrac{3}{4}\) giữ nguyên
\(2< 3\\ =>\dfrac{1}{2}< \dfrac{3}{4}\)
\(b,MSC:20\\ \dfrac{5}{4}=\dfrac{5\times5}{4\times5}=\dfrac{25}{20}\)
\(\dfrac{15}{20}\) giữ nguyên
\(25>15\\ \Rightarrow\dfrac{5}{4}>\dfrac{15}{20}\)
\(c,MSC:35\\ \dfrac{5}{7}=\dfrac{5\times5}{7\times5}=\dfrac{25}{35}\\ \dfrac{7}{5}=\dfrac{7\times7}{5\times7}=\dfrac{49}{35}\\ 25< 49\\ \Rightarrow\dfrac{5}{7}< \dfrac{7}{5}\)
theo mk thi mk so sanh the nay :
5x5 co tan cung la 5
4x6 co tan cung la 4 suy ra A>B
chỉ vậy thôi
a) 35 : 5 và (35 x 4) : (5 x 4)
35:5= 7
(35 x 4) : (5 x 4) = 140 : 20 =7
=> 35 : 5 = (35 x 4) : (5 x 4)
b) 105 : 15 và (105 : 5) : (15 : 5)
105:15 =7
(105 : 5) : (15 : 5)= 7 : 3= 2 (dư 1)
=>105 : 15 > (105 : 5) : (15 : 5)
Ta có: 14/25 < 15/25 = 3/5
Ta có: 1 - 3/5 = 2/5 ; 1 - 5/7 = 2/7 ; 2/5 > 2/7
Nên 3/5 < 5/7
Vậy 14/25 < 5/7
Các câu còn lại tương tự
\(\dfrac{a+5}{a+4}=\dfrac{a+4+1}{a+4}=1+\dfrac{1}{a+4}\)
\(\dfrac{a+15}{a+14}=\dfrac{a+14+1}{a+14}=1+\dfrac{1}{a+14}\)
Ta có: a+4<a+14
=>\(\dfrac{1}{a+4}>\dfrac{1}{a+14}\)
=>\(\dfrac{1}{a+4}+1>\dfrac{1}{a+14}+1\)
=>\(\dfrac{a+5}{a+4}>\dfrac{a+15}{a+14}\)
\(\text{Vì }\dfrac{5}{4}=\dfrac{35}{28}>\dfrac{30}{28}=\dfrac{15}{14}\Rightarrow\dfrac{5}{4}>\dfrac{15}{14}\text{ hay }\dfrac{a+5}{a+4}>\dfrac{a+15}{a+14}\)
\(\text{Vậy }\dfrac{a+5}{a+4}>\dfrac{a+15}{a+14}\)