042557

\(\frac{1}{\left(x+5\right)\left(x+4\right)}+\frac{1}{\left(x+6\right)\left(x+5\right)}+\frac{1}{\left(x+6\right)\left(x+7\right)}=\frac{1}{18}\)

\(\Leftrightarrow\frac{1}{x+4}-\frac{1}{x+5}+\frac{1}{x+5}-\frac{1}{x+6}+\frac{1}{x+6}-\frac{1}{x+7}=\frac{1}{18}\)

 \(\Leftrightarrow\frac{1}{x+4}-\frac{1}{x+7}=\frac{1}{18}\)

\(\Leftrightarrow\frac{\left(x+7\right)-\left(x+4\right)}{\left(x+7\right)\left(x+4\right)}=\frac{1}{18}\)

\(\Leftrightarrow\frac{3}{x^2+11x+28}=\frac{1}{18}\) 

\(\Leftrightarrow x^2+11x+28=54\)

\(\Leftrightarrow x^2+11x=26\)

\(\Leftrightarrow x^2+11x-26=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-13\end{cases}}\)

` 5/8 -x = 7/6`

`=> x= 5/8 -7/6`

`=>x= 30/48 - 56/48`

`=>x=-26/48`

`=>x=-13/24`

__

`1/6 + 1/5 :x =-7 /18`

`=>  1/5 :x =-7 /18 -1/6`

`=>  1/5 :x =-7 /18- 3/18`

`=>  1/5 :x =-5/9`

`=>x= 1/5 : (-5/9)`

`=>x= 1/5 xx (-9/5)`

`=>x=-9/25`

a: x=5/8-7/6=15/24-28/24=-13/24

b: =>1/5:x=-7/18-1/6=-7/18-3/18=-10/18=-5/9

=>x=-1/5:5/9=-9/25

\(\dfrac{5}{8}-x=\dfrac{7}{6}\\ x=\dfrac{5}{8}-\dfrac{7}{6}\\ x=\dfrac{15}{24}-\dfrac{28}{24}\\ x=-\dfrac{7}{24}\)

\(\dfrac{1}{6}+\dfrac{1}{5}:x=-\dfrac{7}{18}\\ \dfrac{1}{5}:x=-\dfrac{7}{18}-\dfrac{1}{6}\\ \dfrac{1}{5}:x=-\dfrac{7}{18}-\dfrac{3}{18}\\ \dfrac{1}{5}:x=-\dfrac{5}{9}\\ x=\dfrac{1}{5}:\left(-\dfrac{5}{9}\right)\\ x=-\dfrac{9}{25}\)

`a)`

`6 \times 1 = 6`

`6 \times 4 = 24`

`6 \times 6 = 36`

`b)`

`12 \div 6 = 2`

`18 \div 6 = 3`

`48 \div 6 = 8`

`c)`

`6 \times 5 = 30`

`30 \div 6 = 5`

`30 \div 5 = 6`

B. 1/6 nhé!

B

b

sorry!em mới học l5 thui

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

2: x-1/5=2/11

=>x=2/11+1/5=21/55

3: x-5/6=16/42-8/56

=>x-5/6=8/21-4/28=5/21

=>x=5/21+5/6=15/14

4: x/5=5/6-19/30

=>x/5=25/30-19/30=6/30=1/5

=>x=1

5: =>|x|=1/3+1/4=7/12

=>x=7/12 hoặc x=-7/12

6: x=-1/2+3/4

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

11: x-(-6/12)=9/48

=>x+1/2=3/16

=>x=3/16-1/2=-5/16

1)x= 1/4

2)x= 2/11+ 1/5

   x= 21/55

3)x - 5/6 = 5/21

   x         = 5/21+5/6

   x         = 15/14

4)x/5 = 5/6 + -19/30

   x:5 = 1/5

   x    = 1/5.5

   x    = 1

5) |x| - 1/4 = 6/18

    |x|           = 6/18 - 1/4

    |x|            =7/12

⇒x= 7/12 hoặc -7/12

6)x = -1/2 +3/4

   x= 1/4

7) x/15 = 3/5 + -2/3

   x:15  = -1/15

  x        = -1/15. 15

  x        = -1

8)11/8 + 13/6 = 85/x  

       85/24      = 85/x

  ⇒      x           = 24

9) x - 7/8 = 13/12

   x          = 13/12 + 7/8

   x          = 47/24

10)x - -6/15 = 4/27  

     x            = 4/27 + (-6/15)

    x             = -34/135

11) -(-6/12)+x = 9/48

                    x= 9/48 - 6/12

                    x = -5/16

12) x - 4/6 = 5/25 + -7/15

      x -4/6  =  -4/15

     x           = -4/15 + 4/6

    x             = 2/5

5 x 6 = 30       2 x 6 = 12        3 x 6 = 18        4 x 6 = 24

6 x 5 = 30       6 x 2 = 12        6 x 3 = 18        6 x 4 = 24

Tính nhẩm:

5 x 6 = 30       2 x 6 = 12        3 x 6 = 18        4 x 6 = 24

6 x 5 = 30       6 x 2 = 12        6 x 3 = 18        6 x 4 = 24

30 : 6 = 5       12 : 6 = 2         18 : 6 = 3         24 : 6 = 4

30 : 5 = 6       12 : 2 = 6         18 : 3 = 6         24 : 4 = 6

Học tốt <3

5 x 6 = 30        2 x 6 = 12       3 x 6 = 18      4 x 6 = 24

6 x 6 = 30        6 x 2 = 12       6 x 3 = 18      6 x 4 = 24

30 : 6 = 5         12 : 6 = 2       18 : 6 = 3       24 : 6 = 4

30 : 5 = 6         12 : 2 = 6       18 : 3 = 6       24 : 4 = 6

x= 3/8

b, x=1/2

c, x=3/2

d, x=3

a, x + \(\frac{1}{4}=\frac{5}{8}\)

            x = \(\frac{5}{8}-\frac{1}{4}\)

            x = \(\frac{5}{8}-\frac{2}{8}\)

            x = \(\frac{3}{8}\)

b, x - \(\frac{1}{3}=\frac{1}{6}\)

            x = \(\frac{1}{6}+\frac{1}{3}\)

            x = \(\frac{1}{6}+\frac{2}{6}\)

            x = \(\frac{3}{6}\)

            x = \(\frac{1}{2}\)

c, \(Xx\frac{3}{5}=\frac{9}{10}\)

         \(X=\frac{9}{10}:\frac{3}{5}\)

        \(X=\frac{9}{10}x\frac{5}{3}\)

        \(X=\frac{45}{30}\)

        \(X=\frac{3}{2}\)

d, \(X:\frac{1}{6}=18\)

        \(X=18x\frac{1}{6}\)

        \(X=3\)

a,x=3/8

b,x=1/2

c,x=3/2

d,x=3