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
500 + 100 = 100 + 500
300 - -500 = 300 + 200
400 - -200 = 200 + 400
500 + x = 100 + 500
500 + x = 600
x = 600 - 500
x = 100
300 - x = 300 + 200
300 - x = 500
x = 300 - 500
x = -200
400 - x = 200 + 400
400 - x = 600
x = 400 - 600
x = -200
500 + x = 100 + 500
500 + x = 600
x = 600 - 500
x = 100
300 - x = 300 + 200
300 - x = 500
x = 500 - 300
x = 200
400 - x = 200 + 400
400 - x = 600
x = 600 - 400
x = 200
tk mk mk tk lại