1) 2x^2-4x-2.5=0 x^2-2x-5/4=0,(x-1)^2=9/4,x-1=土3/2,x1=5/2,x2=-1/2.2)-y^2+2y+3=0,y^2-2y-3=0,(y-3)(y+1)=0,y1=3,y2=-1.3)（x-1）^2-2（x-1）-3=0,由2)得x-1=3,或x-1=-1,∴x1=4,x2=0.