Let f(r) dr = 12, f(r) dr = -8, g(x) dr = -10, g(r) dr = -13, %3D Use these values to evaluate the given definite integrals. a) (S(r) + g(x)) dr = b) / | (S(x) g(x)) dr = c) (3f(x) +2g(2)) dr: (af(x)+g(x)) dr = 0, d) Find the value a such that a =