27. Incorrect. The answer is true not false. It does not matter what units are in your equations provided you use the same units when you apply the equations. I use the units P = 25, Q = 1, Ed = -0.5 and Es = 0.6. Since Ed = b(P/Q), b = Ed*Q/P = -0.5*1/25 = -0.02. a = Q - bP = 1 - (-0.02)25 = 1.5 => Qd = 1.5 - 0.02P. Since Es = d(P/Q), d = Es*Q/P = 0.6*1/25 = 0.024. c = Q - dP = 1 - (0.024)25 = 0.4 => Qs = 0.4 + 0.024P.