(x-1)(y+1-2x)=2005=5×401 共可组合四解 x-1=1,y+1-2x=2005,即x=2,y=2008 x-1=5,y+1-2x=401,即x=6,y=412) x-1=401,y+1-2x=5,即x=402,y=406 x-1=2005,y+1-2x=1,即x=2006,y=4012
求方程 2x2-xy-3x+y+2006=0 的正整数解,
(x-1)(y+1-2x)=2005=5×401 共可组合四解 x-1=1,y+1-2x=2005,即x=2,y=2008 x-1=5,y+1-2x=401,即x=6,y=412) x-1=401,y+1-2x=5,即x=402,y=406 x-1=2005,y+1-2x=1,即x=2006,y=4012