a)

   \(\frac{2}{3}+\frac{1}{3}:x=\frac{3}{5}\)

   \(\frac{1}{3}:x=\frac{3}{5}-\frac{2}{3}\)

    \(\frac{1}{3}:x=\frac{-1}{15}\)

     \(x=\frac{1}{3}:\frac{-1}{15}\)

    \(x=-5\)

b)

     \(\frac{10}{3x}+\frac{67}{4}=-13.25\)

      \(\frac{10}{3x}+\frac{67}{4}=\frac{-53}{4}\)

       \(\frac{10}{3x}=\frac{-53}{4}+\frac{67}{4}\)

       \(\frac{10}{3x}=\frac{7}{2}\)

      \(\Rightarrow10.2=7.3x\)

            \(20=21x\)

            \(x=\frac{20}{21}\)

c)

        x+30%x=-1.3

        x+0.3x=-1.3

        x (1+0.3) = -1.3

        x . 1.3 = -1.3

        x = -1.3 : 1.3

        x = 1

d)

          \(\left(\frac{14}{5x}-50\right):\frac{2}{3}=51\)

           \(\frac{14}{5x}-50=51.\frac{2}{3}\)

             \(\frac{14}{5x}-50=34\)

             \(\frac{14}{5x}=34+50\)

              \(\frac{14}{5x}=84\)

               \(84.5x=14\)

              420x = 14

                   \(x=\frac{1}{30}\)

a, \(\frac{2}{3}+\frac{1}{3}:x=\frac{3}{5}\)

=> \(\frac{1}{3}:x=\frac{3}{5}-\frac{2}{3}\)

=>\(\frac{1}{3}:x=\frac{-1}{15}\)

=> \(x=\frac{1}{3}:\frac{-1}{15}\)

=> \(x=\frac{-1}{5}\)

mình sai chỗ kết quả cuối bằng -5 nhé

a,  3 x + 1 : 3 4 = 81

3 x - 3 = 3 4

x – 3 = 4

x = 7

Vậy x = 7

b,  3 x + 3 . 3 x + 1 = 729

3 2 x + 4 = 3 6

2x + 4 = 6

x = 1

Vậy x = 1

c,  2 x + 3 . 2 x = 128

2 2 x + 3 = 2 7

2x + 3 = 7

x = 2

Vậy x = 2

d,  23 + 3 x = 5 6 : 5 3

23 + 3 x = 5 3

23 + 3x = 125

3x = 102

x = 34

Vậy x = 34

e,  2 x + 2 x + 4 = 272

2 x + 2 x . 2 4 = 272

2 x ( 1 + 2 4 ) = 272

2 x . 17 = 272

2 x = 16

2 x = 2 4

x = 4

Vậy x = 4

\(53^2+53.94+47^2=53^2+2.53.47+47^2=\left(53+47\right)^2=100^2=10000\)

\(\left(3x-2\right)^2-2\left(3x-2\right).\left(3x-5\right)+\left(5-3x\right)^2=\left(3x-2-3x+5\right)^2=3^2=9\) 

trong đó\(\left(5-3x\right)^2=\left(3x-5\right)^2\)

1: =>|x-4|+|x+2|=0

=>x-4=0 và x+2=0

=>\(x\in\varnothing\)

2: =>x^2-x-6=3x+5

=>x^2-4x-11=0

=>x^2-4x+4-15=0

=>(x-2)^2-15=0

=>x=căn 15+2 hoặc x=-căn 15+2

3: =>x^2-x=3x+5

=>x^2-4x-5=0

=>(x-5)(x+1)=0

=>x=-1 hoặc x=5

\(a,\Rightarrow12x-91=101\\ \Rightarrow12x=192\\ \Rightarrow x=16\\ b,\Rightarrow x:23+45=133\\ \Rightarrow x:23=88\\ \Rightarrow x=\dfrac{88}{23}\\ c,\Rightarrow\left(6x-39\right):7=3\\ \Rightarrow6x-39=21\\ \Rightarrow6x=60\\ \Rightarrow x=10\\ d,\Rightarrow3x-24=\dfrac{148}{73}\\ \Rightarrow3x=\dfrac{1900}{73}\\ \Rightarrow x=\dfrac{1900}{219}\\ e,\Rightarrow\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\\ f,\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\\ d,\left(9-x\right)^3=64=4^3\\ \Rightarrow9-x=4\\ \Rightarrow x=5\\ h,\Rightarrow x=27\\ i,\Rightarrow6x=312\cdot12=624\cdot6\\ \Rightarrow x=624\\ j,\Rightarrow\left(19x+104\right):14=25-42=-17\\ \Rightarrow19x+104=-238\\ \Rightarrow19x=-342\\ \Rightarrow x=-18\)

⇔ 4x - 10 = 2 - x

⇔ 4x + x = 2 + 10 ⇔ 5x = 12 ⇔ x = 12/5

Vậy: S = {12/5}

b) (3x + 1) = (3x + 1)2

⇔ (3x + 1)2 - (3x + 1) = 0

⇔ (3x + 1)[(3x + 1) - 1] = 0

ĐKXĐ:x ≠ 1

Quy đồng mẫu hai vế của phương trình ta được:

Khử mẫu hai vế, ta được:

(2x + 3)(x - 1) + 2(x2 + x + 1) = 4x2 - 1

⇔ 2x2 + x - 3 + 2x2 + 2x + 2 = 4x2 - 1

⇔ 3x - 1 = -1

⇔ 3x = 0 ⇔ x = 0 (thỏa mãn điều kiện)

Vậy: S = {0}

3: \(\Leftrightarrow a-15=0\)

hay a=15