Exercise 9-2 Which lines in the following are not valid? Explain why in each case. 1) 1. (x)[(Hx ⋅ Kx) ⊃ Mx] p 2. (∃x)(

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Exercise 9-2 Which lines in the following are not valid? Explainwhy in each case.
1) 1. (x)[(Hx ⋅ Kx) ⊃ Mx] p
2. (∃x)(Hx ⋅ Kx) p
3. Hx ⋅ Kx 2 El
4. Mx 1,3 MP
5. (∃x)Mx 4, EG
(3)1. (∃x)(Fx ⋅ ∼ Mx) p
2. (x)[(Gx ∨ Hx) ⊃ Mx] p
3. (Gy ∨ Hy) ⊃ My 2,Ui
4. Fy ⋅ ∼ My 1, EI
5. ∼ My 4, Simp
6. ∼ (Gy ∨ Hy) (4) 3,5MT
7. (∃x) ∼ (Gx ∨ Hx) 6, EG
(5)1. (∃x)[(Px ⋅ Qx) ∨ Rx] p
2. (x) ∼ Rx p
3. (∃x)(Px ∨ Rx) 1 Simp
4. Px ∨ Rx 3 EI
5. ∼ Px 2,4 DS
6. (x) ∼ Px 5, UG
7. ∼ Py 6,UI
8. (z) ∼ Pz 7, UG