8.1÷(x+2)=1.8x-2=8.1÷1.8x-2=4.5x=6.5
8.1/(x+2)=1.88.1=1.8(x+2)8.1=1.8x+3.61.8x=8.1-3.61.8x=4.5x=2.5
x十2=8.1÷1.8x=2.5