Let P(x) = x² - 3x - 7, and let Q(x) and R(x) be two quadratic polynomials also with the coefficient of x² equal to 1. David computes each of the three sums P + Q, P + R, and Q + R and is surprised to find that each pair of these sums has a common root, and these three common roots are distinct. If Q(0) = 2, then find R(0).