Suppose the curves r₁(t) = (3t² - 3t - 9, 3t + 10, 2 - t) and r₂(s) = (s² - 4, 4s + 3, s + 2) both lie on a surface S and intersect at P(-3, 7, 3). Find an equation of the tangent plane to the surface S at the point P(-3, 7, 3).