Thế này nhé bạn:
3x+(1+2+3)=18
3x+6 =18
3x =18-6
3x =12
x =12:3
x =4
\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)=18\)
\(\Rightarrow\left(x+x+x\right)+\left(1+2+3\right)=18\)
\(\Rightarrow3x+6=18\)
\(\Rightarrow3x=18-6\)
\(\Rightarrow3x=12\)
\(\Rightarrow x=12:3\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
~ Ủng hộ nhé