Let P and Q be two quadratic polynomials, such that P(z)=3z2+4z+3 and Q(z)=3z2+6z+15.
Furthermore, the product of P(x) and Q(y) for some x,y∈R is 20. Find their sum, ie, P(x)+Q(y).
It can be expressed as ba for coprime positive integers a and b. Find a+b.