5.6 Proof 1

Solution for Proof 1 on page 5.6
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Not all frogs are green. ~∀x(Fx→Gx) Some frogs are not green. ∃x(Fx&~Gx) But here you are putting the negation in front of the parenthesis? ~∀x(Ax → Cx) ∃x~(Ax & Cx)