2. (5+5 points) Let ICS(P) and let 4,4,0 S(P). (a) Given T F 16 = 4), construct the proof (derivation) of the formal theorem TF (0[4/x] = 0[4/x]), (i.e. T F (@[x := 4] = 0[x := 4).) (b) Give a derivation (Hilbert style proof) of the following formal theorem 6 = 4, y = 0 + 9 = (that is, 4 4 4,4 H 0 640). 2. (5+5 points) Let ICS(P) and let 4,4,0 S(P). (a) Given T F 16 = 4), construct the proof (derivation) of the formal theorem TF (0[4/x] = 0[4/x]), (i.e. T F (@[x := 4] = 0[x := 4).) (b) Give a derivation (Hilbert style proof) of the following formal theorem 6 = 4, y = 0 + 9 = (that is, 4 4 4,4 H 0 640)