-2x-40=(5-x)-(-15+60)

=>-2x-40=5-x+15-60

=>-2x+x=5+15-60+40

=>-x=20-60+40=0

=>x=0

-2x-40=(5-x)-(-15+60)

-2x-40=5-x-45

-2x+x=5-45+40

-x       =0

x        =0

\(-2x-40=5-x-45\)

\(\Leftrightarrow-x=0\)

\(\Leftrightarrow x=0\)

-2x - 40 = (5 - x) - (-15 + 60)

-2x - 40 = (5 - x) - 45

-2x - 40 = -40 - x

-2x - x = 40 - 40

      -3x = 0

         x = 0

2(x - 4) - 3(x + 7) = 14

    2x - 8 - 3x - 21 = 14

                 -x - 29 = 14

                        -x = 14  + 29

                        -x = 43 

                         x = -43

-7(5 - x) - 2(x - 10) = 15

-35 + 7x - 2x + 20 = 15

              -15 + 5x = 15

                       5x = 15 + 15

                       5x = 30

                         x = 6

         \(-2x-40=\left(5-x\right)-\left(-15+60\right)\)

\(\Leftrightarrow\)\(-2x-40=5-x+15-60\)

\(\Leftrightarrow\)\(-2x-40=-x-40\)

\(\Leftrightarrow\)\(-2x+x=40-40\)

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

Vậy....

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

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

\(3x=-20\)

\(x=-20:3\)

\(x=\frac{-20}{3}\)

-2x-40=(5-x)-(-15+60)

=> -2x - 40 = 5 - x + 15 +60

=> -2x - 40 = 80 - x

=> -2x + x = 80 + 40

=> -x = 120

-2x-40=(5-x)-(-15+60)

-2x - 40 = 5 - x - 45

-2x - 40 = -x - 40

-2x + x = -40 + 40

-1x = 0

x = 0

-2x-40=(5-x)-(-15+60)

-2x-40=5-x+15-60

-2x-40=5+15-60-x

-2x-40=-40-x

-2x=x

TH1:x=0 thì -2x0=0(chọn)

TH2:x>0 thì -2x<0 mà x>0(loại)

TH3:x<0 thì -2x>0 mà x<0(loại)

Vậy x=0

\(-2x-40=\left(5-x\right)-\left(-15+60\right)\)

\(-2x-40=5-x+15-60\)

\(-2x+x=5+15-60+40\)

\(-x=0\Rightarrow x=0\)

-2x-40=(5-x)-(-15+60)

<=>-2x-40=5-x+15-60

<=>-2x-40=5-x-45

<=>-2x-40-5+x+45=0

<=>80-x=0

<=>x=80

Vậy x=80

Trả lời:

\(-2x-40=\left(5-x\right)-\left(-15+60\right)\)

\(\Leftrightarrow-2x-40=5-x-45\)

\(\Leftrightarrow-2x-40=x-40\)

\(\Leftrightarrow-2x-x=40-40\)

\(\Leftrightarrow-3x=0\)

\(\Leftrightarrow x=0\)

Vậy\(x=0\)

Hok tốt!

Good girl

\(-2x-40=\left(5-x\right)-\left(-15+60\right)\)

\(-2x-40=5-x+15-60\)

\(-2x-40=-40-x\)

   \(-2x+x=-40+40\)

              \(-x=0\)

                  \(x=0\)