Answer
-61
Work Step by Step
$57_{10} = (32 + 16 + 8 + 1)10 = 111001_2 → 00111001 − 118_{10}
= −(64 + 32 + 16 + 4 + 2)_{10}$
$= −1110110 → 01110110 → 10001001 → 10001010.$
So the 8-bit representations of 57 and −118 are $00111001 $ and $10001010$ respectively.
Adding the 8-bit representations gives
as
00111001+1001010=1100011
Since the leading bit of this number is a 1, the answer is negative.
Converting back to decimal form gives
$11000011 → 00111100→−001111012 = −(32 + 16 + 8 + 4 + 1)_{10} = −6110.$
So the answer is −61.
