Dados los polinomios P(x) = –7x 4 + 6x 2 + 6x + 5, Q(x) = –2x 2 + 2 + 3x 5 , R(x) = x 3 – x 5 + 3x 2 , S(x) = 9x 3 – 4x 2 y T(x) = x+2. Calcula:  P(x) + Q(x)  P(x) + R(x)  S(x) + P(x)  T(x) +R(x) ​