若x,y,z满足3x+7y+z=1,4x+10y+z=2006,求分式2005x+2005y+2005z/x+3y的值.

题目

若x,y,z满足3x+7y+z=1,4x+10y+z=2006,求分式2005x+2005y+2005z/x+3y的值.

答案

3x+7y+z=1 (1),4x+10y+z=2006 (2) (2)-(1), x+3y=2005 (3) 2005x+2005y+2005z/x+3y=x+y+z (3) 乘2：2x+6y=4010 (4)(1)-(4):x+y+z=-40092005x+2005y+2005z/x+3y=x+y+z =-4009