b^2-4ac/4a=5/4 ①a+b+c=0 ②c=1 ③由①得,b^2-c=5/4把③代入①,则b^2=9/4所以,b=±3/2把③代入②,则a=-c-b=-1-b当b=+3/2时,a=5/2,c=1当b=-3/2时,a=1/2,c=1
题不对吧?