Given a bit pattern that you are told is a 2's complement number, you can find out its decimal equivalent in the following way. If the first bit is 0, then the number is positive and you simply convert the binary number to decimal. If the first bit is 1, the number is negative and we negate it to find its absolute value, since -(-x) = x. To negate any 2's complement number, Flip all the bits and add 1.

     1001011100011110     (original)             ??

     0110100011100001     (flip all bits)
                   +1     (add 1)
    -----------------
     0110100011100010     (2's complement)      26,850

Since the number was original negative, the decimal equivalent of 1001011100011110 is -26,850.