x + 100 = -300

      x = -300 -100

      x = -400

x + 700 = 900 - 700

x + 700 = 200

         x = 200 - 700

        x = -500

_x+100=-300

_x=-300-100

_x=-400

_x+700=200

_x=200-700

_x=-500

x + 100 = 300 - 600

x + 100 = - 300

x          = - 300 - 100

x          = - 400

\(7=\dfrac{7}{1}=\dfrac{7\cdot100}{1\cdot100}=\dfrac{700}{100}\\ =>C\)

x=-500

x + 100 = 200 - 700 + 100

x + 100 = - 500 + 100

x + 100 = - 400

x          = - 400 - 100

x          = - 500

x+100=200-700+100

x+100=-500+100

x+100=-400

x=-400-100

x=-500

x + 100 = 200 - 700 - 100

x + 100 = - 500 - 100

x + 100 = - 600

x          = - 600 - 100

x          = - 700

x + 100 = 200 - 700 - 100

x + 100 = -600

x = -600 - 100

x = -700

x+100=200-700-100

x+100=-500-100

x+100=-600

x=-600-100

x=-700

x + 100 = 700 - 300

x + 100 = 400

x = 400 - 100

x = 300

x+100=700-300

x+100=400

x      =400-100

x       =300

 mk k bn ở câu này rùi k mk nhé

x + 100 = 700-300

x+100=400

x=400-100

x=300

k mk nha

x + 100 = 900 - 700

x + 100 = 200

x = 200 -100

x = 100

x + 100 = 900 - 700

x + 100 =200

x           = 200 - 100

x           = 100

Vậy x = 100

x + 100 = 900 - 700

x + 100 = 200

         x = 200 - 100

         x =100

x + 300 = 700 - 100

x + 300 = 600

x            = 600 - 300

x             = 300

Vậy x = 300

x+300=600

x=600-300

x=300

ai tk minh minh tk lai

x + 300 = 700 - 100

x + 300 = 600

x = 600 - 300

x = 300

x + 100 = 200 + 700

x + 100 = 900

x          = 900 - 100

x           = 800

x+100=900

x=900-100

x=800

x  +100 = 200 + 700

x + 100 = 900

x = 900 - 100

x = 800 

x - 100 = 700 - 600

x - 100 = 100

x          = 100 + 100

x          = 200

x - 100 = 700 - 600

x - 100 = 100

x         = 100 + 100

x         = 200

tk mk đi mk tk bn rồi