2x+5m=18-x,3x=18-5m,3x-18=-5m5m=3(6-x)
因m为正整数,x的正整数:
x=1,2,3,4,5,6,代入得m=3,12/5,9/5,6/5,3/5,0
故m为正整数3时,x=1为其解