原式可变为x(1+y)=30-y,显然y不等于-1,所以x=(30-y)/(y+1)=31/(y+1)-1,所以y+1能整除31,因此y+1可取1,31,-1,-31,代入可得x分别等于30,0,-32,-2,因此整数解为x1=30,y1=1,x2=0,y2=30,x3=-32,y3=-2,x4=-2,y4=-32...