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15 tháng 5 2019

#)Giải :

   15/2 - y        = 45/7 : 5

   15/2 - y        = 9/7

            y        = 15/2 - 9/7

            y        = 6/3/14 = 87/14

     #~Will~be~Pens~#

15 tháng 5 2019

15/2 - y * 5 = 45/7

          y * 5 = 15/2 - 45/7

          y * 5 = 105/14 - 90/14

          y * 5 = 15/14

          y      = 15/14 : 5

          y      = 15/14 x 1/5

          y      = 15/70

          y      = 3/14

3 tháng 3 2023

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`

19 tháng 3 2023

`1)1/2:2/3 .... 2/3 : 1/2`

`=>1/2xx3/2 .... 2/3xx2`

`=>3/4 .... 4/3`

Vì `3/4 < 1` và `4/3>1` 

`=>3/4<4/3`

__

`4/7:2/5 ... 4/7 : 3/5`

`=>4/7xx5/2....4/7xx5/3`

`=>20/14...20/21`

`=>10/7...20/21`

Vì `10/7>1` và `20/21<1` 

`=>10/7>20/21`

__

`4/15:4/7....2/5xx10/3`

`=>4/15xx7/4...20/15`

`=>7/15...20/15`

Vì `7<20` nên `7/15<20/15`

__

`5/6...15/18-11/18`

`=>5/6...4/18`

Ta có : MSC : `18`

`5/6 = 15/18`

Vì `15>4` nên `5/6 > 4/18`

19 tháng 3 2023

`2)2/3=(2xx6)/(3xx6)=12/18`

`7/9=(7xx7)/(9xx7)=49/63`

`6/5=(6xx3)/(5xx3)=18/15`

`2/3=(2xx5)/(3xx5)=10/15`

`5/9=(5xx5)/(9xx5)=25/45`

`49/56=(49:7)/(56:7)=7/8`

`6/8=(6xx7)/(8xx7)=42/56`

`2/9=(2xx7)/(9xx7)=14/63`

`49/56=(49:7)/(56:7)=7/8`

28 tháng 1 2022

4 : 9 = \(\dfrac{4}{9}\)                         8 : 11 =\(\dfrac{8}{11}\)             7 : 15 =\(\dfrac{7}{15}\)

15 : 5 =  \(\dfrac{15}{5}=\dfrac{3}{1}\)                     63 : 21 =\(\dfrac{63}{21}\)           45 : 9 =\(\dfrac{45}{9}=\dfrac{5}{1}\)

6 : 18 =  \(\dfrac{6}{18}=\dfrac{1}{3}\)                       144 :  24 =\(\dfrac{244}{24}\)       7 =\(\dfrac{7}{1}\)

15 =  \(\dfrac{15}{1}\)                            10 = \(\dfrac{10}{1}\)                0 =\(\dfrac{0}{1}\)

\(4:9=\dfrac{4}{9};15:5=\dfrac{15}{5}=3;6:18=\dfrac{6}{18}=\dfrac{1}{3}\\ 15=\dfrac{15}{1};8:11=\dfrac{8}{11};63:21=\dfrac{63}{21}=3;144:24=\dfrac{144}{24};10=\dfrac{10}{1}\\ 7:15=\dfrac{7}{15};45:9=\dfrac{45}{9}=5;7=\dfrac{7}{1};0=0\)

1.

\(\left(572\cdot7+266\right)\cdot\left(366\cdot9-168\cdot18\right)\cdot\left(346\cdot6-348\right)\)

\(=\left(286\cdot7\cdot2+133\cdot2\right)\cdot\left(366\cdot9-168\cdot2\cdot9\right)\cdot\left(173\cdot6\cdot2-174\cdot2\right)\)

\(=\left(2002\cdot2+133\cdot2\right)\cdot\left(366\cdot9-336\cdot9\right)\cdot\left(1038\cdot2-174\cdot2\right)\)

\(=\left[2\cdot\left(2002+133\right)\right]\cdot\left[9\cdot\left(366-336\right)\right]\cdot\left[2\cdot\left(1038-174\right)\right]\)

\(=2\cdot2135\cdot9\cdot30\cdot2\cdot864\)

\(=4270\cdot9\cdot30\cdot2\cdot864\)

\(=\left(4270\cdot30\right)\cdot9\cdot2\cdot864\)

\(=\left(427\cdot10\right)\cdot\left(3\cdot10\right)\cdot9\cdot2\cdot864\)

\(=\left(427\cdot3\right)\cdot\left(10\cdot10\right)\cdot9\cdot2\cdot864\)

\(=1281\cdot100\cdot9\cdot2\cdot864\)

\(=\left(1281\cdot100\right)\cdot\left(9\cdot2\cdot864\right)\)

\(=\left(1281\cdot100\right)\cdot15552\)

\(=\left(1281\cdot15552\right)\cdot100\)

\(=19922112\cdot100\)

\(=1992211200\)

2.

\(\left(1+3+5+7+...+97+9\right)\cdot\left(45\cdot3-15\cdot2-45\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left(15\cdot3\cdot3-15\cdot2-15\cdot3\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left[15\cdot\left(3\cdot3\right)-15\cdot2-15\cdot3\right]\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left(15\cdot9-15\cdot2-15\cdot3\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left[15\cdot\left(9-2-3\right)\right]\)

\(=\left(1+3+5+7+...+97+9\right)\cdot15\cdot4\)

\(=\left[\left(1+3+5+7+...+97\right)+9\right]\cdot\left(15\cdot4\right)\)

Trong \(\left(1+3+5+7+...+97\right)\) có số số hạng là:

        \(\left(97-1\right)\div2+1=49\) ( số hạng )

\(\Rightarrow\left[\left(1+3+5+7+...+97\right)+9\right]\cdot\left(15\cdot4\right)\)

\(=\left[\left(97+1\right)\cdot49\div2\right]\cdot\left(15\cdot4\right)\)

\(=2401\cdot60\)

\(=\left(2401\cdot6\right)\cdot10\)

\(=14406\cdot10\)

\(=144060\)

3.

\(\left(180\div15-132\div11\right)\cdot\left(57869-297\div11\cdot108\right)\)

\(=\left(12-12\right)\cdot\left(57869-297\div11\cdot108\right)\)

\(=0\cdot\left(57869-297\div11\cdot108\right)\)

\(=0\)

Sửa lại bài 2; dòng 11 ( từ đề bài bài 2 ):

\(=\left\{\left[\left(97+1\right)\cdot49\div2\right]+9\right\}\cdot\left(15\cdot4\right)\)

\(=\left(2401+9\right)\cdot\left(15\cdot4\right)\)
\(=2410\cdot\left(15\cdot4\right)\)

\(=2410\cdot60\)

\(=\left(241\cdot10\right)\cdot\left(6\cdot10\right)\)

\(=\left(241\cdot6\right)\cdot\left(10\cdot10\right)\)

\(=1446\cdot10\)

\(=14460\)

6 tháng 3 2022

4/3

1/7

27/28

3/5

6 tháng 3 2022

a) \(3-\dfrac{5}{3}=\dfrac{1}{3};\dfrac{15}{7}-2=\dfrac{1}{7}\)

28 tháng 8 2021

a) \(\dfrac{5}{8}:4\times\dfrac{1}{2}=\dfrac{5}{8}\times\dfrac{1}{4}\times\dfrac{1}{2}=\dfrac{5}{64}\)

b) \(\dfrac{7}{15}:\dfrac{14}{45}\times\dfrac{12}{11}=\dfrac{7}{15}\times\dfrac{45}{14}\times\dfrac{12}{11}=\dfrac{18}{11}\)

11 tháng 5 2020

rút gọn phân số :

4/5+21/15=4/5+7/5=11/5

8/9-25/45=8/9-5/9=3/9

tính :

5/6+2/7+15/6=5/6+15/6+2/7

=10/3+2/7=76/21

7/8-9/6.7/8=7/8-21/16=-7/16 

chúc bạn học tốt !!!

26 tháng 2 2017

a) 2/5+9/5=11/5

b) 15/45+25/30=7/6

c) 28/32+45/72=3/2

d) 8/28+5/30=19/42

bài 2

a) x - 4/5 =4/5 + (3/7+3/5)

x-4/5=4/5+36/35

x-4/5=64/35

x=64/35+4/5

x=92/35

b) x-7/35=4/5

x=4/5+7/35

x=1

nhớ tk m nhé

26 tháng 2 2017

a = 18/5

b = 3/9 + 5/6 = 6/18 + 25/18  = 31/18

c = 7/8 + 5/8 = 12/8

d = 4/14 + 1/6 = 14/42 + 7/42 = 21/42 -= 7/14

b2

x - 4/5 = 4.5 + ( 3/7 + 3/5 )

x - 4/5 = 49/35

           x = 49/35 + 4/5

              x = 77/35

x - 7/35 = 4/5

             x = 4/5 + 7/35

                 x = 1

mình ko chắc chắn đâu

mình nghĩ mình làm sai

              

1 tháng 4 2022

   Bài 1: Tính           

 1/2  +  7/20= 10/20 + 7/20 = 17/20               

8/15   x   15/1= 2/3