b) 200 x 4 = .800.....              300 x 2 = ..600....

200 x 2 = .400.....             300 x 3 = ...900...

400 x 2 = ...800...             500 x 1 = ..500....

100 x 4 = ..400....             100 x 3 = .300.....

800

400

800

400

600

900

500

300

ai giúp mình với

500 + x = 100 + 500

500 + x = 600

          x = 600 - 500

          x = 1001

300 - x = 300 + 200

300 - x = 500

         x = 300 - 500

         x = -200

400 - x = 200 + 400

400 - x = 600

         x = 400 - 600

         x = -200

k mk nha mk k l

ại ^_^

500 + 100 = 100 + 500

300 + 200 =  300 + 200

400 + 200  = 200 + 400

500+x=100+500

vay x =100

300-x=300+200

vay x= - 200

400-x=200+400

vay x= -200

300 + 400 x 2 + 100

= 300 + 800 + 100

= 1100 + 100

= 1200

300 + 400 x 2 + 100

= 300 + 800 + 100

= 1100 + 100

= 1200

tk mk nha 

hihi <3 

300+400x2+100=700x2+100

                       =1400+100

                       =15000

x + 100 = 200 - 300

x + 100 = - 100

          x = 100 - 100

          x = 0

x - 300 = 400 - 500

x - 300 = -100

        x = -100 + 300

        x = 200

k mik mik k lại

x + 100 = 200 - 300

x + 100 = -100

x = -100 - 100

x = -200

x - 300 = 400 - 500

x - 300 = -100

x = -100 + 300

x = 200 

1 bang-200

2bang200

x - 300 = 400 - 100 - 100

x - 300 = 200

x = 200 + 300

x = 500.

x = 500 nhé bạn

x = 500

\(x+100=0\)

\(x=-100\)

x + 100 = 200 - 300 - 300 + 400

x + 100 = -100 - 300 + 400

x + 100 = -400 + 400

x + 100 = 400 - 400

x + 100 = 0

          x = 0 - 100

          x = -100

x+100=200-300-300+400

x+100=0

x=0-100

x=-100

Tìm x

a) x + 300 = 400 - 100

x + 300 = 300

x = 300 - 300

x = 0

b) x - 600 = 400 + 600

x - 600 = 1000

x = 1000 - 600

x = 400

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a) x + 300 = 400 - 100

   x + 300 = 300

   x            = 300 - 300

x              = 0

b) x - 600 = 400 + 600

    x - 600 = 1000

    x           = 1000 - 600

   x           = 400 

x+300=400-100

x+300=300

      x=300-300

       x=0

x-600=400+600

x-600=1000

       x=1000+600

        x=1600

x - 100 = 200 + 900

x - 100 = 1100

x         = 1100 + 100

x         = 1200

x + 100 = 300 - 400

x + 100 = - 100

x          = - 100 - 100

x          = - 200

x+100=200+900

x+100=1000

x=1000-100

x=900

x+100=300-400

x+100=-100

x=-100-100

x=-200

X-100=200+900

X-100=1100

X       =1100+100

X       =1200

a)  (a-b)-(c-b)-a=a-b-c+b-a=(a-a)+(b-b)-c=0+0-c=-c

1)

a) (a-b) - (c-b) - a= a - b - c + b - a = -c

b) -(300 - 400) + (300 - 400) + 100 = 100

2) a) 4x - 20 =  50 - ( 30 -3x)

        4x - 20 = 50 - 30 + 3x

        4x - 3x = 50 - 30 + 20= 40

        x          = 40

b) 100 - (-5x) = 40 - (-4x +10)

    100 + 5x    = 40 + 4x -10

    5x - 4x       = 40 - 10 -100

    x                = -70

c) (-50) + (-7x) = 100 - 8x

     -7x + 8x      = 100 + 50

      x                = 150

Bài 1.

a) \(\left(a-b\right)-\left(c-b\right)-a\)

\(=a-b-c+b-a\)

\(=\left(a-a\right)+\left(-b+b\right)-c\)

\(=-c\)

b)\(-\left(300-400\right)+\left(300-400\right)+100\)

\(=-300+400+300-400+100\)

\(=\left(-300+300\right)+\left(400-400\right)+100\)

\(=100\)

Bài 2.

a)\(4x-20=50-\left(30-3x\right)\)

\(\Leftrightarrow4x-20=50-30+3x\)

\(\Leftrightarrow4x-20=20+3x\)

\(\Leftrightarrow x=40\)

Vậy x = 40

b)\(100-\left(-5x\right)=40-\left(-4x+10\right)\)

\(\Leftrightarrow100+5x=40+4x-10\)

\(\Leftrightarrow x=-70\)

Vậy x = -70

c)\(\left(-50\right)+\left(-7x\right)=100-8x\)

\(\Leftrightarrow-50-7x=100-8x\)

\(\Leftrightarrow x=150\)

Vậy x = 150

Linz