\(\frac{3}{4}\cdot\frac{8}{5}\cdot\frac{5}{9}=\frac{2}{3}\)

\(\frac{3}{7}:\frac{3}{14}:\frac{1}{2}=4\)

cậu ghi lòi  giải ra được không

a) \(\frac{3}{4}x\frac{8}{5}x\frac{5}{9}=\frac{3x8x5}{4x5x9}=\frac{120}{180}=\frac{2}{3}\)

b) \(\frac{6}{7}:\frac{3}{14}:\frac{1}{2}=\frac{6}{7}x\frac{14}{3}x\frac{1}{2}=\frac{84}{42}=2\)

1/   Suy ra: -35 + 7x - 2x + 20 = 15

                5x - 15 = 15

                 5x = 30

                  x = 6

2/  Suy ra:  4x - 20 - 3x - 21 = -19

                   x - 41  = -19

                    x  = 22

3/   Suy ra:   8 - 4x + 3x - 15 = 14

                    -7 -x = 14

                      x = -7 -14

                      x = -21

4/    Suy ra:   7x - 63 - 30 + 5x = -6 + 11x

                      7x + 5x - 11x = -6 +63 + 30

                       x   =    87

5/    Suy ra:  -21x +35 + 14x - 28 = 28

                       -21x + 14x = 28 +28 - 35

                         -7x = 21

                             x= -3

6/     Suy ra:  20 - 5x + 7x - 14 = -2

                        2x   =   -8

                          x = -4

7/    Suy ra:   4x +15 -5x = 7

                      -x = -8

                        x = 8

 8/   Suy ra:   5x - 35 +30 -10x = 20

                      -5x - 5 = 20

                          -5x = 25

                            x = -5

9/    Suy ra:     35 - 7x + 5x - 10 = 15

                         -7x + 5x = 15 +10 - 35

                        -2x = -10

                          x = 5

4/5 x 15/11 x 2/9 = 8/33

4/7 x 2/5 + 4/7 x 3/5 = 4/7

( 5/7 + 7/8 ) x 2 =  89/28

2/14 + 3/7 - 3/14 x 2 = 1/7 

tk mình nhé, mk nhanh nhất

4/5 x 15/11 x2/9

= 4x15x2/5x11x9

= 4x5x3x2/5x11x3x3

= 8/33

4/7x2/6+4/7x3/5

=4/7x(2/6+3/5)

=4/7x 14/15

=8/15

`7 xx 3/14 -1/14`

`= 21/14 -1/14`

`= 20/14`

`=10/7`

__

`3/2 + 7/4 xx 2/5`

`= 3/2 + 14/20`

`= 3/2 + 7/10`

`= 15/10 +7/10`

`= 23/10`

__

`9/8 : 3 + 7/3 : 3`

`= 9/8 xx 1/3 + 7/3 xx 1/3`

`=1/3 xx ( 9/8 + 7/3)`

`= 1/3 xx 83/24`

`= 83/72`

__

`2 : 3/4 - 5/8 xx 4/3`

`= 2 xx 4/3 - 5/8 xx 4/3`

`= 4/3 xx ( 2-5/8)`

`= 4/3 xx ( 16/8 -5/8)`

`= 4/3 xx 11/8`

`= 44/24`

`=11/6`

` @ \color{Red}{sushiteam}`

a: \(\dfrac{-8}{3}\cdot\dfrac{15}{24}=\dfrac{-8}{24}\cdot\dfrac{15}{3}=\dfrac{-1}{3}\cdot5=-\dfrac{5}{3}\)

b: \(=\dfrac{3}{4}\cdot\dfrac{1}{-9}=\dfrac{-1}{12}\)

c: \(x=-\dfrac{7}{6}+\dfrac{5}{8}=-\dfrac{13}{24}\)

d: \(x=-\dfrac{14}{25}-\dfrac{3}{4}=\dfrac{-56-75}{100}=\dfrac{-131}{100}\)

a: =>x=-7/6+5/8=-13/24

b: =>x=-14/25-3/4=-131/100

c: \(x=\dfrac{-33}{26}:\dfrac{-9}{13}=\dfrac{33}{26}\cdot\dfrac{13}{9}=\dfrac{11}{3}\cdot\dfrac{1}{2}=\dfrac{11}{6}\)

d: \(x=\dfrac{4}{9}:\dfrac{5}{3}=\dfrac{4}{9}\cdot\dfrac{3}{5}=\dfrac{12}{45}=\dfrac{4}{15}\)

( 2 x y + 2/15 ) x 3 = 4/5

( 2 x y + 2/15 )      = 4/5 : 3 

( 2 x y + 2/15 )      =   4/15

 2 x y                    = 4/15 - 2/15 

2 x y                     =     2/15

     y                      =     2/15 :2 

   y                          =    1/15

(2 x y + 2/15) x 3 = 4/5 

2 x y + 2/15) = 4/5 : 3 

2 x y + 2/15 = 4/15 

2 x y = 4/15 - 2/15 

2 x y = 2/15 

y = 2/15 : 2 

y = 1/15 

7/9 x (2 - 1/3 x y) = 14/15 

(2 - 1/3 x y) = 14/15 : 7/9 

(2 - 1/3 x y) = 6/5 

2 - y = 6/5 x 1/3 

2 - y = 2/5 

y = 2/5 + 2 

y = 12/5 

4/21 + 5 x y - 8/7 = 1/3 

4/21 + 5 x y = 1/3 + 8/7 

4/21 + 5 x y = 31/21 

5 x y = 31/21 - 4/21 

5 x y = 9/7 

y = 9/7 : 5 

y = 9/35 

7/12 x y - 3/12 x y = 5 

y x (7/12 - 3/12) = 5 

y x 1/3 = 5 

y = 5 : 1/3 

y = 15 

Bài 1: 

a: -8/12<0<-3/-4

b: -56/24<0<7/3

c: 4/25<1<15/13

=>-4/25>-15/13

Bài 2: 

a: =-60/45=-4/3

b: =4/15-3/2-8/5=8/30-45/30-48/30=-85/30=-17/6

a) x+30%x=-1.31

=> 100%x+30%x=-1.31

=>x.(100%+30%)=-1.31

=>x.13/10=-1.31=-1.31:13/10=-131/130

b) (x-1/2):1/3+5/7=9+5/7

=>(x-1/2).3+5/7=68/7

=>(x-1/2).3=68/7-5/7=9

=>x-1/2=9:3=3

=>x=3+1/2=3 1/2( hỗn số)

c) 1/2x-3/4=14/9.3/7

=>1/2x-3/4=2/3

=>1/2x=2/3+3/4=17/12

x=17/12:1/2=17/12.2=17/6

d) - 5/6 -x = 7/12+ -1/3

=>- 5/6 -x = 7/12+ -4/12=1/4

=> x = -5/6 -1/4=-13/12

e) x + 3/-15 = 1/3

=> x= 1/3 - -3/15 =1/3+3/15

=> x=5/15 + 3/15=8/15

f) (4,5 -2 x). (-1 4/7)=11/14

=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6

=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3

=>x= -19/3: -2x=19/6

Chúc bn thi HKII tốt!!!

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