∵2008(x+y)^与2009l1/2y-1l互为相反数∴2008(x+y)^+2009┃1/2y-1┃=0 2008(x+y)²=0 1/2y-1=0(1)∴x=-2 y=2(2)-x²+y^-1=-(-2)²+2^-1=-4+1/2=-7/2=-3.5