3x-(x-5)/2,的(x+2)/0.3的值互为相反数,
所以3x-(x-5)/2,+(x+2)/0.3=0
3x-(x-5)/2,+10(x+2)/3=0
18x-3(x-5)+20（x+2)=0
18x-3x+15+20x+40=0
35x+55=0
x=-11/7