13 - ( 2 x X - 1) = 4                                                                             4 x X - 12 = 40

      ( 2 x X - 1) = 13 - 4                                                                       4 x X       = 40 + 12

      ( 2x X -1)   = 9                                                                              4 x X       = 52

       2 x X      = 9 + 1                                                                               X        = 52 : 4

       2 x X      = 10                                                                                   X        = 13

            X      = 10 : 2

           X      =    5

d) 12x 156 - 12 x 55 - 12

= 12 x ( 156 - 55 - 12 )

= 12 x 100

= 1200

e ) 12 x 11 + 21 x 11 + 11 x 33

= ( 12+ 21 + 33) x 12

= 66 x 11

= 726

g) 132 x 11 - 11 x 32 - 54 x 11

= ( 132 - 32 - 54 ) x 11

= 46 x 11

= 506

d) 12 x 156 - 12 x 55 - 12 = 12x(156 - 55 - 1 ) = 12 x 100 = 1200

e) 12 x 11 + 21 x 11 + 11 x 33 = 11  x ( 12 + 21 + 33 ) = 11  x 66 = 726

g) 132 x 11 - 11 x 32 - 54 x 11 = 11 x ( 132 - 32 - 54 ) = 11 x 46 = 506

d) \(12\times156-12\times55-12\) \(=12\times\left(156-55-1\right)\)

                                                         \(=12\times100=1200\)

e) \(12\times11+21\times11+11\times33\)\(=11\times\left(12+21+33\right)=11\times66=726\)

g) \(132\times11-11\times32-54\times11\) \(=11\times\left(132-32-54\right)=11\times46=506\)

lớp mấy ba

a) \(12+x+\left(-5\right)=-18-2x\)

\(\Rightarrow12+x-5=-18-2x\)

\(\Rightarrow x+7+18+2x=0\)

\(\Rightarrow3x=-25\)

\(\Rightarrow x=-\dfrac{25}{3}\) 

b) \(\left(-14\right)-x+\left(-15\right)=-10+\left(4-2x\right)\)

\(\Rightarrow-14-x-15=-10+4-2x\)

\(\Rightarrow-x-29=-2x-6\)

\(\Rightarrow-x+2x=-6+29\)

\(\Rightarrow x=23\)

c) \(x-\left(-19\right)-\left(-11\right)=-\left(3x+40\right)\)

\(\Rightarrow x+19+11=-3x-40\)

\(\Rightarrow x+30=-3x-40\)

\(\Rightarrow x+3x=-40-30\)

\(\Rightarrow4x=-70\)

\(\Rightarrow x=-\dfrac{35}{2}\)

Bài 2:

a) 11. x = -55

x = -55 : 11

x = -5

Vậy x = -5

b) -3 . x = -12

x = -12 : (-3)

x = 4

Vậy x = 4

c) 3x - 12 = -48

3x = -48 + 12

3x = -36

x = -36 : 3

x = -12

Vậy x = -12

d) 10 + 23 . (2x - 10) = -36

23 . (2x - 10) = -36 - 10

23 . (2x - 10) = -46

2x - 10 = -46 : 23

2x - 10 = -2

2x = -2 + 10

2x = 8

x = 8: 2

x = 4

Vậy x = 4

f) | 2x - 1| + 3 = 8

|2x - 1| = 8 - 3

|2x - 1| = 5

\(\Rightarrow\left[\begin{matrix}2x-1=5\\2x-1=-5\end{matrix}\right.\Rightarrow\left[\begin{matrix}2x=6\\2x=-4\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=3\\x=-2\end{matrix}\right.\)

Vậy x = 3 hoặc x = -2

g) |2x² - 3| - 4 = 11

|2x²- 3| = 11 + 4

|2x² - 3| = 15

\(\Rightarrow\left[\begin{matrix}2x^2-3=15\\2x^2-3=-15\end{matrix}\right.\Rightarrow\left[\begin{matrix}2x^2=18\\2x^2=-12\end{matrix}\right.\Rightarrow\left[\begin{matrix}x^2=9\\x^2=-6\end{matrix}\right.\Rightarrow\left[\begin{matrix}x^2=3^2\\\left(loại\right)\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=3\\\end{matrix}\right.\)

Vậy x = 3.

Bài 1:

\((-48) . 72 +36 . (-304) \)

\(=\left[\left(-48\right).\left(36.2\right)\right]+36.\left(-340\right)\)

\(=\left[\left(-48\right).2\right].36+36.\left(-340\right)\)

\(=\left(-96\right).36+36.\left(-304\right)\)

\(=36.\left[\left(-96\right)+\left(-304\right)\right]\)

\(=36.\left(-400\right)\)

\(=-14400\)

\(=\dfrac{12}{15}\times\left(\dfrac{26}{11}-\dfrac{9}{11}-\dfrac{6}{11}\right)=\dfrac{12}{15}\times\dfrac{11}{11}=\dfrac{12}{15}=\dfrac{4}{5}\)

= 12/15 x (26/11 - 9/11 - 6/11)

= 12/15 x 11/11

= 12/15

help

\(=\dfrac{11}{12}\left(\dfrac{2}{7}+\dfrac{4}{7}+\dfrac{1}{7}\right)=\dfrac{11}{12}\cdot1=\dfrac{11}{12}\)

=11/12

11/12 nha