-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....

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

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

\(3x=-20\)

\(x=-20:3\)

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

(-25)-(5.x-3)=4

5.x-3 = -25 - 4

5.x-3=-29

5.x=-26

x=-26/5

x=-5,2

5.x-6=20-(12-6)

5.x-6=20-6

5.x-6=14

5.x=20

x=20:5

x=4

vậy x=4

1/
-25-(5x-3)=4
-25-4=5x-3
-25-4+3=5x
5x= -26
x= -26/5
2/
5x-6=20-(12-6)
5x = 20-12+6+6
5x = 20
x = 20/5 = 4
3/
-2x -40 = (5-x) -(-15+60
-2x -40 = 5-x +15-60
-2x +x = 5+15-60+40
-x = 0
x=0

(X+40)x15+(60+x)*5=2000

x*15+40*15+60*5+x*5=2000

x*(15+5)+600+300=2000

x*20+900=2000

x*20=2000-900

x*20=1100

x=1100:20

x=55

-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+x=5+15-60+40

-x=0

=> x=0

các bạn cho mk vài li-ke cho tròn 230 với 

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

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

<=> -x=0 

=> x=0

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

-2x-40=5-x-45

-2x-40=x-5-45

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

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

x-(-38)=x-(-40)

x-x=(-38)-(-40)

x-x=2

?????

mk tih hay that

-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=(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

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

\(\Leftrightarrow-x=0\)

\(\Leftrightarrow x=0\)

a: x=600

b: x=6