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Use rules of inference to show that if the premises x(P(x) Q(x)), x(Q(x) R(x)), and R(a), where a is in the domain, are true, then the conclusion P(a) is true.

Premises: x(P(x) Q(x)), x(Q(x) R(x)) and R(a)

Conclusion: P(a)

Prove that if x3 is irrational, then x is irrational.