According to Vieta theorem, c/a =-2b+ 1 = 1-b, and b=0 or 2.

-b/a=-2a=a-3, and a= 1 is obtained. When b=0, y = x+2x+ 1, and the intersection with the x axis is only 1, which is inconsistent with the meaning of the question, so a = 1 and b=