Question 1131580
<pre>
1.(A&B)&#8835;C
2. B&~C       / ~A
(indirect proof

          | 3.  ~~A        AIP
          | 4.  A       3, DN
          | 5.  B       2, simp. 
          | 6.  A&B     4,5, conj.
          | 7.  C       1,6, MP
          | 8.  ~C&B    2, commutation
          | 9.  ~C      8, simp.
          |10.  C&~C    7,9, conj.
11. ~A     lines 3-10     IP

Edwin</pre>