3x+3(x+10)=3003x+3x+30=3006X=300一30x=270÷6X=45
3x+3（x+10）=3003x+3x+30=3006x=270x=45
3x+3x+300=3006x=0x=0
3x+3(x+10)＝300 3x+3x+30＝300 6x+30＝300 6x＝270 x＝45
