a)

\(\begin{array}{l}{(1,2)^3}.x = {(1,2)^5}\\x = {(1,2)^5}:{(1,2)^3}\\x = {(1,2)^2}\\x = 1,44\end{array}\)

Vậy \(x = 1,44\).

b)

\(\begin{array}{l}{\left( {\frac{2}{3}} \right)^7}:x = {\left( {\frac{2}{3}} \right)^6}\\x = {\left( {\frac{2}{3}} \right)^7}:{\left( {\frac{2}{3}} \right)^6}\\x = \frac{2}{3}\end{array}\)

Vậy \(x = \frac{2}{3}\).

CÂU 1:\(\frac{2}{35}:\left(\frac{3}{5}+\frac{3}{7}\right)\)

           \(=\frac{2}{35}:\frac{36}{35}\)

           \(=\frac{1}{18}\)

CÂU 2:\(\frac{1}{2}\cdot\frac{25}{6}-\left(\frac{4}{3}+\frac{5}{3}\right)\)

    \(=\frac{25}{12}-3\)

     \(=-\frac{11}{12}\)

CÂU 3:\(5\frac{5}{7}-\left(\frac{3}{7}+2\frac{3}{5}\right):\frac{4}{5}\)

   \(=\frac{40}{7}-\left(\frac{3}{7}+\frac{13}{5}\right):\frac{4}{5}\)

   \(=\frac{40}{7}-\frac{106}{35}:\frac{4}{5}\)

   \(=\frac{40}{7}-\frac{53}{14}\)

   \(=\frac{27}{14}\)

`5/3+(−2/7)−(−1,2)`

`=5/3-2/7+1,2`

`=5/3-2/7+6/5`

`=175/105-30/105+126/105`

`=271/105`

\(\dfrac{5}{3}+\dfrac{-2}{7}-\left(-1,2\right)\)

\(=\dfrac{5}{3}+\dfrac{-2}{7}+1,2\)

\(=\dfrac{5}{3}-\dfrac{2}{7}+\dfrac{6}{5}\)

\(=\dfrac{175}{105}-\dfrac{30}{105}+\dfrac{126}{105}\)

\(=\dfrac{175-30+126}{105}\)

\(=\dfrac{271}{105}\)

a, \(\dfrac{5}{7}+\left(\dfrac{3}{5}+\dfrac{-5}{7}\right)\)
\(=\dfrac{5}{7}+\dfrac{-5}{7}+\dfrac{3}{5} =0+\dfrac{3}{5}=\dfrac{3}{5}\)

b, \(=\dfrac{-3}{4}-\dfrac{15}{14}:\dfrac{-5}{7}+\left(-1\right)^2=\dfrac{-3}{4}-\dfrac{-3}{2}+1=\dfrac{-3}{4}-\dfrac{-6}{4}+1=\dfrac{3}{4}+1=\dfrac{7}{4}\)

 c, \(\dfrac{-5}{9}+\left(\dfrac{-2}{3}\right)^2.\left(20\%-1.2\right)=\dfrac{-5}{9}+\dfrac{4}{9}x\left(\dfrac{1}{5}-\dfrac{6}{5}\right)=\dfrac{-5}{9}+\dfrac{4}{9}x\left(-1\right)=\dfrac{-5}{9}+\dfrac{-4}{9}=-1\)

Bài 1:

a) \(\dfrac{5}{7}+\left(\dfrac{3}{5}+\dfrac{-5}{7}\right)\)\(=\left(\dfrac{5}{7}+\dfrac{-5}{7}\right)+\dfrac{3}{5}\)\(=0+\dfrac{3}{5}=\dfrac{3}{5}\)

b) \(\dfrac{-3}{4}-\dfrac{15}{14}:\dfrac{-5}{7}+\left(-1\right)^2\)\(=\dfrac{-3}{4}-\dfrac{15}{14}:\dfrac{-5}{7}+1\)\(=\dfrac{-3}{4}-\dfrac{-3}{2}+1\)

                                            \(=\dfrac{3}{4}+1\)\(=\dfrac{7}{4}\)

a

=5/7 * (5+6-4/11)

= 5/7+7/11

=5/11

b

=1,2 - 9 + 2,5

=  -7,8 + 2,5 

= -5,3

a

=5/7 * (5+6-4/11)

= 5/7+7/11

=5/11

b

=1,2 - 9 + 2,5

=  -7,8 + 2,5 

= -5,3

a, 5/7 * (5/11+6/11-4/11)

= 5/7* (-3/11) = -15/77

`1,2×15/4+16/7×-85/8-1,2 × 5 3/4 - 16/7 × -71/8`

`=6/5xx15/4+16/7xx(-85)/8-6/5xx23/4-16/7xx(-71)/8`

`=6/5xx(15/4-23/4)+16/7xx[(-85/8)-(-71/8)]`

`=6/5xx(-8/4)+16/7xx(-14/8)`

`=-32/5`

7+7=14

\(7+7=8\)

7+7=8 nha

Ý BẠN LÀ VẬY HẢ?

1-(537,5%+ x - 7 và 5/24) : 2/3=1,2

1-(537,5/100 + x - 173/24) =1,2 x 2/3

1-(5375/1000 + x - 173/24) =4/5

43/8 + x - 173/24 = 1-4/5

43/8 + x - 173/24 = 1/5

43/8 + x = 1/5 + 173/24

43/8 + x= 889/120

    x = 889/120 - 43/8

    x = 61/30

Vậy x= 61/30