Question

giúp mình giải bài toán.......

1)3x-6=5x+2

2)15-x=4x-5

3)x-15=6+4x

4)-12+x=5x-20

5)7x-4=20+3x

6)5x-7=-21-2x

7)x+15=20-4x

8)17-x=7-6x

9)-4|x-2|=-8

10)-7|x+4|=2.(-7)

Answer 1

minh moi hoc lop 5 thoi

Answer 2

1) 3x - 6=  5x + 2

5x - 3x = -6 - 2

2x = -8

x = -4

2) 15 - x = 4x - 5

4x + x = 15 + 5

5x = 20

x = 4

Tương tự như trên 

Answer 3

1) 3x - 6 = 5x + 2

  3x - 5x = 2 + 6

        -2x = 8

           x = 8 : (-2)

           x = -4

2) 15 - x = 4x - 5

    -x - 4x = -5 - 15

         -5x = -20

            x = -20 : (-5)

            x = 4

 

Answer 4

5) 7x - 4 = 20 + 3x

  7x - 3x =  20 + 4

         4x = 24

          x = 24 : 4

          x = 6

6) 5x - 7 = -21 - 2x

  5x + 2x = -21 + 7

         7x = -14

           x = -14 : 7

           x = -2

Answer 5

7) x + 15 = 20 - 4x 

    x + 4x = 20 - 15

          5x = 5

            x = 5 : 5

            x = 1

8) 17 - x = 7 - 6x

   -x + 6x = 7 - 17

          5x = -10

            x = -10 : 5

            x = -2

Answer 6

9) -4|x - 2| = -8

⇒     |x - 2| = -8 : (-4)

⇒     |x - 2| = 2

⇒ \(\left[{}\begin{matrix}x-2=2\\x-2=-2\end{matrix}\right.\)

⇒ \(\left[{}\begin{matrix}x=2+2\\x=-2+2\end{matrix}\right.\)

⇒ \(\left[{}\begin{matrix}x=4\\x=0\end{matrix}\right.\)

      Vậy x = 4; x = 0

 

Answer 7

3)x - 15 = 6+4x

-15 -6 = 4x -x 

3x = -21

x= -7

4)-12 + x = 5x - 12 

-12 + 12 = 5x - x 

4x = 0 

x =0

Answer 8

10) -7|x + 4| = 2 . (-7)

⇒    -7|x + 4| = -14

⇒       |x + 4| = -14 : (-7)

⇒       |x + 4| = 2

⇒ \(\left[{}\begin{matrix}x+4=2\\x+4=-2\end{matrix}\right.\)

⇒  \(\left[{}\begin{matrix}x=2-4\\x=-2-4\end{matrix}\right.\)

⇒ \(\left[{}\begin{matrix}x=-2\\x=-6\end{matrix}\right.\)

     Vậy x = -2; x = -6