x + 1 + x + 2 +3= 123
x+(1+2+3)=123
x+6=123
x =123-6
x =117
Ta có: x+ 1+ x+ 2+ 3 = 123
=>2\(\times\) x+6 =123
=> x= (123-6):2
x=117/2
x+ ( 1+2+3 ) = 123
x+ 6 = 123
x =123-6
x =117
x+1+x+2+3=123
2x+1+2+3=123
2x+6=123
2x=123-6
2x=117
x=117:2
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