1) \(\left(5x-1\right)\left(5x+1\right)=25x^2-7x+15\)

\(\Leftrightarrow25x^2-1=25x^2-7x+15\)

\(\Leftrightarrow7x=16\Leftrightarrow x=\dfrac{16}{7}\)

2) \(\left(3x-5\right)\left(x+1\right)-\left(3x-1\right)\left(x+1\right)=x-4\)

\(\Leftrightarrow3x^2-2x-5-3x^2-2x+1=x-4\)

\(\Leftrightarrow5x=0\Leftrightarrow x=0\)

a) x+x+x+91=-2

    x.3          =(-2)-91

    x.3          = -93

    x             =(-93):3

    x             = -31

Trl:

a) \(x+x+x+91=-2\)

\(\Rightarrow x.3+91=-2\)

\(\Rightarrow x.3=-2-91\)

\(\Rightarrow x.3=-93\)

\(\Rightarrow x=-93:3\)

\(\Rightarrow x=-31\)

b) \(-125-\left(3x+1\right)=-2.27\)

\(\Rightarrow-125-\left(3x+1\right)=-54\)

\(\Rightarrow\left(3x+1\right)=-125-\left(-54\right)\)

\(\Rightarrow\left(3x+1\right)=-125+54\)

\(\Rightarrow\left(3x+1\right)=-71\)

\(\Rightarrow3x=-71-1\)

\(\Rightarrow3x=-72\)

\(\Rightarrow x=-72:3\)

\(\Rightarrow x=-24\)

Hc tốt

thank bn nha

a) 5(-x - 2) = 0

-x - 2 = 0

-x = 0 + 2

-x = 2

x = -2 (nhận)

Vậy x = -2

b) (-4).x = 26

x = 26 : (-4)

x = -13/2 (loại)

Vậy không tìm được x là số nguyên thỏa mãn đề bài

c) -152 - (3x + 1) = (-2).27

-152 - (3x + 1) = -54

3x + 1 = -152 + 54

3x + 1 = -98

3x = -98 - 1

3x = -99

x = -99 : 3

x = -33 (nhận)

Vậy x = -33

a, 5.(- \(x\) - 2) = 0

       - \(x\) - 2    = 0

         \(x\)         = - 2

b, (-4).\(x\)       = 26

           \(x\)       = 26 : (-4)

          \(x\)      = - \(\dfrac{13}{2}\) (loại) vì \(x\)\(\in\) Z)

c; -152 - (\(3x\) + 1) = (-2).(27)

     -152 - 3\(x\) - 1   = - 54

               3\(x\)        = -54 + 1 + 152

              3\(x\)         = - 99

               \(x\)          = - 99: 3

                \(x\)         = - 33

-152-(3x+1)=-2.(-77)

-152-(3x+1)=154

3x+1 = 154 + 152

3x + 1 = 306

3x = 306 - 1

3x = 305

x = \(\frac{305}{3}\)

Trả lời :

- 152 - ( 3x + 1 ) = - 2 . ( - 77 )

- 152 - ( 3x + 1 ) = 154

=> 3x - 1 = ( - 152 ) - 154

=> 3x - 1 = - 306

3x = - 306 + 1

3x = - 305

=> x = - 305 : 3

x = \(\frac{-305}{3}\)

Vậy x = \(\frac{-305}{3}\)

x + x + x + 91 = -2

x + x + x = -2 - 91

x + x + x = -93

3x = -93

x = -93 : 3

x = -31

-152 - (3x + 1) = (-2) . (-27)

-152 - (3x + 1) = 54

3x + 1 = -152 - 54

3x + 1 = -206

3x = -206 - 1

3x = -207

x = -207 : 3

x = -69

|5x + 1| = 11

5x + 1 = 11 hay 5x + 1 = -11

5x = 11 - 1 hay 5x = -11 - 1

5x = 10 hay 5x = -12

x = 10 : 5 hay x = -12 : 5

x = 2 hay x = -2,4

Mà x ∈ Z

x = 2

n: (-8)*x+17=-23

=>\(x\cdot\left(-8\right)=-23-17=-40\)

=>\(x\cdot8=40\)

=>\(x=\dfrac{40}{8}=5\)

o: \(\left(-15\right)\cdot x=10\left(-4\right)-5\)

=>\(x\cdot\left(-15\right)=-40-5=-45\)

=>\(x\cdot15=45\)

=>\(x=\dfrac{45}{15}=3\)

p: \(\left(-3\right)\cdot x-4=2\cdot\left(-7\right)+4\)

=>\(\left(-3\right)\cdot x-4=-14+4=-10\)

=>\(x\left(-3\right)=-10+4=-6\)

=>\(3x=6\)

=>\(x=\dfrac{6}{3}=2\)

q: x+x+x+91=-2

=>\(3x+91=-2\)

=>\(3x=-2-91=-93\)

=>\(x=-\dfrac{93}{3}=-31\)

r: \(-152-\left(3x+1\right)=\left(-2\right)\cdot\left(-27\right)\)

=>\(-152-3x-1=54\)

=>\(-153-3x=54\)

=>\(3x=-153-54=-207\)

=>\(x=-\dfrac{207}{3}=-69\)

a: \(\Leftrightarrow\left(2x-5\right)^3=225-4\cdot100=125\)

=>2x-5=5

=>2x=10

hay x=5

b: \(\Leftrightarrow\left(x-2\right)\left(x-5\right)=0\)

hay \(x\in\left\{2;5\right\}\)

c: =>x-5-2x-7=-8

=>-x-12=-8

=>x+12=8

hay x=-4

\(\left(2x-5\right)^3=15^2-4.5^2\)

\(\Leftrightarrow\left(2x-5\right)^3=125\)

\(\Leftrightarrow2x-5=5\)

\(\Leftrightarrow x=5\)

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\(\left(x-2\right)\left(15-3x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\15-3x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\)

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\(\left(x-5\right)-\left(2x+7\right)=-8\)

\(\Leftrightarrow x-5-2x-7=-8\)

\(\Leftrightarrow-x=4\)

\(\Leftrightarrow x=-4\)

Hình như đề sai!

( - 152 ) - ( 3x+1 ) = (-2) . (-77)

 (- 152 ) - (3x +1 ) = 154

                3x +1   = (-152)- 154

                 3x + 1 = -306

                 3x       = - 306 - 1

                 3x       = - 307

                   x       = - 307 : 3

                   x       = - 307 / 3 ( dấu / là chỉ phân số) 

x = - 307 / 3