a. \(x-\dfrac{3}{2}=\dfrac{5}{6}\)

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

\(x=\dfrac{14}{6}=\dfrac{7}{3}\)

b. \(\dfrac{2}{5}\) x \(x=\dfrac{2}{3}\)

\(x=\dfrac{2}{3}:\dfrac{2}{5}\)

\(x=\dfrac{2}{3}\) x \(\dfrac{5}{2}\)

\(x=\dfrac{5}{3}\)

`x - 3 / 2 = 5 / 6`

`x = 5 / 6 + 3 / 2`

`x = 5 / 6 + 9 / 6`

`x = 14 / 6 = 7 / 3`    Vậy `x = 7 / 3`

_______________________________

`2 / 5 xx x = 2 / 3`

`x = 2 / 3 : 2 / 5`

`x = 2 / 3 . 5 / 2`

`x = 5 / 3`            Vậy `x = 5 / 3`

______________________________

`2 / 5 : x = 1 / 3`

`x = 2 / 5 : 1 / 3`

`x = 2 / 5 . 3`

`x= 6 / 5`            Vậy `x = 6 / 5`

_______________________________

`x : 5 / 11 = 22`

`x = 22 . 5 / 11`

`x = 10`                 Vậy ` x = 10`

\(2\left(x+56\right)\left(x-6\right)=3^{25}:3^{22}\)

\(\Rightarrow2\left(x+56\right)\left(x-6\right)=3^{25-22}\)

\(\Rightarrow2\left(x+56\right)\left(x-6\right)=3^3\)

\(\Rightarrow\left(x+56\right)\left(x-6\right)=\dfrac{27}{2}\)

\(\Rightarrow x^2-6x+56x-336=\dfrac{27}{2}\)

\(\Rightarrow x^2+50x-336=\dfrac{27}{2}\)

\(\Rightarrow x^2+50x+625-961=\dfrac{27}{2}\)

\(\Rightarrow\left(x+25\right)^2=\dfrac{27}{2}+961\)

\(\Rightarrow\left(x+25\right)^2=\dfrac{1949}{2}\)

\(\Rightarrow\left[{}\begin{matrix}x+25=\sqrt{\dfrac{1949}{2}}\\x+25=-\sqrt{\dfrac{1949}{2}}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\sqrt{\dfrac{1949}{2}}-25\\x=-\sqrt{\dfrac{1949}{2}}-25\end{matrix}\right.\)

\(x^3-6x^2+12x-8=x^3-3.2.x^2+3.2^2.x-2^3\)

\(=\left(x-2\right)^3\)

tại x=22 \(=>B=\left(22-2\right)^3=20^3=8000\)

B=x³-6x²+12x-8
= x³-3.x².2+3.x.2²-2³
= (x-2)³
Thay x = 22 vào biểu thức (x-2)³ ta được:
(22-2)³
=20³ = 8000

1) 2(x + 5) + 3(x + 7) = 41
2x + 10 + 3x + 21 = 41
5x + 31 = 41
5x = 10
x = 2
6) 7(x - 1) + 5(3 - x) = 11x - 10
7x - 7 + 15 - 5x = 11x - 10
2x + 8 = 11x - 10
-9x = -18
x = 2

2) 5(x + 6) + 2(x - 3) = 38
5x + 30 + 2x - 6 = 38
7x + 24 = 38
7x = 14
x = 2

7) 4(2 + x) + 3(x - 2) = 12
8 + 4x + 3x - 6 = 12
7x + 2 = 12
7x = 10
x = 10/7

3) 7(5 + x) + 2(x - 10) = 15
35 + 7x + 2x - 20 = 15
9x + 15 = 15
9x = 0
x = 0

8) 5(2 + x) + 4(3 - x) = 10x - 15
10 + 5x + 12 - 4x = 10x - 15
x + 22 = 10x - 15
9x = 37
x = 37/9

4) 3(x + 4) + (8 - 2x) = 22
3x + 12 + 8 - 2x = 22
x + 20 = 22
x = 2

9) 7(x - 2) + 5(3 - x) = 11x - 6
7x - 14 + 15 - 5x = 11x - 6
2x + 1 = 11x - 6
-9x = -7
x = 7/9

5) 4(x + 5) + 3(7 - x) = 49
4x + 20 + 21 - 3x = 49
x + 41 = 49
x = 8

10) 5(3 - x) + 5(x + 4) = 6 + 4x
15 - 5x + 5x + 20 = 6 + 4x
35 = 6 + 4x
4x = 29
x = 29/4

36x4=144

50x3=150

22x6=132

35x4=140

46:2=23

96:3=32

60:3=20

88:4=22

\(a,\frac{1}{3}+\frac{6}{11}.\frac{22}{5}-\frac{3}{4}:1,5=\frac{1}{3}+\frac{6.2}{5}-\frac{3}{4}:\frac{3}{2}=\frac{1}{3}+\frac{12}{5}-\frac{1}{2}=\frac{10}{30}+\frac{72}{5}-\frac{15}{30}=\frac{67}{30}\)

\(b, 3.3,5.6+2.6,4.9+1,8=18.3,5+18.6,4+1,8=18\left(3,5+6,4\right)+1,8=18.9,9+1,8=1,8.99+1,8=1,8\left(1+99\right)=1,8.100=180\)

b ) 3 x 3,5 x 6 + 2 x 6,4 x 9 + 1,8 

= 18 x 3,5 + 18x 6,4 + 18 x 0,1 

= 18 ( 3,5 + 6,4 + 0,1)

= 18 x 10 

= 180