f(x) = x3 – ax2 + bx + 2 and L(x) = x3 + bx2 – ax + 3 are two polynomials. They intersect at only one point on the x – y plane. If that intersection point lies on the x-axis, then what is value of (a – b)?

1) -5
2) -3
3) 7
4) 0