题目应是 已知(x+y)^2-2x-2y+1=0,求2x^2+5xy+3y^2-2x-3y已知(x+y)^2-2x-2y+1=0,(x+y)^2-2(x+y)+1=0(x+y-1)^2=0x+y-1=0x+y=12x^2+5xy+3y^2-2x-3y=2（x^2+2xy+y^2）+xy+y^2-2x-3y=2(x+y)^2+(x+y)y-2x-3y=2+y-2x-3y=2-2...