Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1
a, đó là : \(\dfrac{5}{10};\dfrac{10}{20};\dfrac{50}{100}....\)
b, Đó là : \(\dfrac{18}{35};\dfrac{72}{140};\dfrac{108}{210}.....\)
c, Là : \(\dfrac{14}{20};\dfrac{35}{50};\dfrac{140}{200}.....\)
2
\(a,\dfrac{3}{2};\dfrac{4}{3};\dfrac{5}{4};\dfrac{6}{5};\dfrac{7}{6}\)
\(b,\dfrac{2}{2};\dfrac{3}{3};\dfrac{4}{4};\dfrac{5}{5};\dfrac{6}{6}\)
\(c,\dfrac{2}{3};\dfrac{3}{4};\dfrac{4}{5};\dfrac{5}{6};\dfrac{6}{7}\)
Bài 1:
a: 1/2=3/6=6/12=9/18
b: 36/70=72/140=216/420=432/840
c: 70/100=7/10=14/20=21/30
Bài 2:
a: 6/5; 7/3; 9/1; 7/2; 8/3
b: 5/5; 7/7; 8/8; 9/9; 10/10
c: 4/5; 3/7; 8/10; 9/26; 7/28
a: =>4/9*a/b=5/27+3/27=8/27
=>a/bb=8/27:4/9=8/27*9/4=72/108=2/3
b: =>9/13*a/b=40/91+1/7=53/91
=>a/b=53/63
`a)4/9xxa/b-1/9=5/27`
`=>4/9xxa/b=5/27+1/9`
`=>4/9xxa/b=5/27+3/27`
`=>4/9xxa/b=8/27`
`=>a/b=8/27:4/9`
`=>a/b=8/27xx9/4`
`=>a/b=2/3`
Vậy `a=2` và `b=3`
__
`b)9/13xxa/b+1/7=40/91`
`=>9/13xxa/b=40/91-1/7`
`=>9/13xxa/b=40/91-13/91`
`=>9/13xxa/b=27/91`
`=>a/b=27/91:9/13`
`=>a/b=27/91xx13/9`
`=>a/b=39/91`
Vậy `a=39` và `b=91`
\(A=9+a+a+....+a\)
\(=9+99a\)
\(=9+99\times2\)
\(=9+198\)
\(=207\)
\(B=140\times3-\left(a+a+a+....+a\right)\)
\(=420-40a\)
\(=420-40\times3\)
\(=420-120\)
\(=300\)