先配平,即原式=a^2-a+1/4+b^2+4b+4+4.25=4+1/4即(a-1/2)^2+(b+2)^2+4.25=4.25化简得(a-1/2)^2+(b+2)^2=0因为(a-1/2)^2和(b+2)^2均为非负数即(a-1/2)^2和(b+2)^2均大于等于0 所以a-1/2=0且b+2=0所以a=1/2,b=-2...