\(\left(\times-\frac{1}{5}\right):\left(\frac{1}{2}+\frac{1}{6}+\cdot\cdot\cdot+\frac{1}{110}\right)=\frac{1}{5}\)

\(\Rightarrow\left(\times-\frac{1}{5}\right):\left(\frac{1}{1\times2}+\cdot\cdot\cdot+\frac{1}{10\times11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(\times-\frac{1}{5}\right):\left(1-\frac{1}{2}+\cdot\cdot\cdot+\frac{1}{10}-\frac{1}{11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(\times-\frac{1}{5}\right):\left(1-\frac{1}{11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(\times-\frac{1}{5}\right):\frac{10}{11}=\frac{1}{5}\)

\(\Rightarrow\left(\times-\frac{1}{5}\right)=\frac{1}{5}\times\frac{10}{11}\)

\(\Rightarrow\times-\frac{1}{5}=\frac{2}{11}\)

\(\Rightarrow\times=\frac{2}{11}+\frac{1}{5}\)

\(\Rightarrow\times=\frac{21}{55}\)

\(\left(x-\frac{1}{5}\right):\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{110}\right)=\frac{1}{5}\)

\(\Rightarrow\left(x-\frac{1}{5}\right):\left(\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+...+\frac{1}{10\times11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(x-\frac{1}{5}\right):\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{10}-\frac{1}{11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(x-\frac{1}{5}\right):\left(1-\frac{1}{11}\right)=\frac{1}{5}\)

\(\Rightarrow\left(x-\frac{1}{5}\right):\frac{10}{11}=\frac{1}{5}\)

\(\Rightarrow x-\frac{1}{5}=\frac{1}{5}\times\frac{10}{11}\)

\(\Rightarrow x-\frac{1}{5}=\frac{2}{11}\)

\(\Rightarrow x=\frac{2}{11}+\frac{1}{5}\)

\(\Rightarrow x=\frac{21}{55}\)

Vậy \(x=\frac{21}{55}\)

\(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{110}\)

\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{10.11}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{10}-\frac{1}{11}\)

\(A=1-\frac{1}{11}\)

\(A=\frac{10}{11}\)

Toan lop 5 ha ma

rút gọn

tôi bị sai sô \(\frac{1}{110}\)nha mọi  người thông cảm

3581/3960 nha bn

K mình nha

a,3x-3+6x-12=5

9x-15=5

9x=20

x=20/9

b,3x-6+6x-6=6

9x-12=6

9x=18

x=2

c,4x+4+5x+10=3x+20

9x+14=3x+20

9x-3x=6

6x=6

x=1

a) 3.(x-1) + 6.(x-2) = 5

3.x - 3 + 6.x - 12 = 5

9.x - 15 = 5

9.x = 5 + 15

9.x = 20

x = \(\frac{20}{9}\)

Vậy x = \(\frac{20}{9}\)

b) 3.(x-2) + 6.(x-1) = 6

  3.x - 6 + 6.x - 6 = 6

9.x - 12 = 6

9.x = 6 + 12

9.x = 18

x = 18 : 9

x = 2

Vậy x = 2

c) 4.(x+1) + 5.(x+2) = 3.x +20

4.x +4 +5.x +10 = 3.x +20

9.x + 14 = 3.x +20

9.x - 3.x = 20 - 14

6.x = 6

x = 6 : 6

x = 1

Vậy x = 1

5.(x - 1) + 6.(x - 2) = 5

5x - 5 + 6x - 12 = 5

11x - 17 = 5

        11x = 5 + 17

         11x = 22

             x = 2

3.(x - 2) + 6.(x - 1) = 6

3x - 6 + 6x - 6 = 6

9x - 12 = 6

       9x = 6 + 12

       9x = 18

        x = 2

5 ( x - 1 ) + 6 ( x - 2 ) = 5

<=> 5x - 5 + 6x - 12 = 5

<=> 11x = 22

<=> x = 2 

Vậy x = 2 

t=(1-1/2+1-1/6+1-1/12+..........+1-1/90+1-1/110)-10/11

t=(1+1+1+...........+1+1)-(1/2+1/6+1/12+.......+1/90+1/110)-10/11

có 10 số 1 vì từ 1/2 đến 109/110 có 10 p/số

t=1.10-(1/1.2+1/2.3+1/3.4+.........+1/9.10+1/10.11)-10/11

t=10-(1-1/2+1/2_1/3+1/3_1/4+.............+1/9-1/10+1/10-1/11)-10/11

t=10-(1-1/11)-10/11

t=10-10/11-10/11

t=10-(10/11+10/11)

t=10-10/11.2

t=10-20/11

t=110/11-20/11

t=90/11