3(x+3)=18+36
3(x+3)=54
x + 3 = 54 : 3
x + 3 = 18
x = 18 - 3
x = 15
3 (x+3)=18+36
3 (x+3)=54
x+3=54÷3
x+3=18
x=18-3
x=15
3(x+3)=18+36
3(x+3)=54
(x+3)=54/3
(x+3)=18
x=18-3
x=15
3( x + 3 ) = 18 + 36
3 ( x +3 ) = 54
x + 3 = 54 : 3
x + 3 = 18
\(\Rightarrow\) x = 15
Vậy x = 15 .
:D