Question 1140648
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1.  A ● ~A   ∴ B
2.  A             1, simplification
3.  A v B         2, addition
4. ~A ● A         1, commutation
5. ~A             4, simplification
6. (A v B) ● ~A   3,5, conjunction
7.  B             6, disjunctive syllogism

Edwin</pre>