Answer
-79
1011 0001
Work Step by Step
Since the two terms are negative you may treat them as positive while you add them and then take 2s compliment of the sum.
convert to binary using continuous divide by two
6/2 = 3 R 0 Least significant
3/2 = 1 R 1
1/2 = 0 R 1 Most significant
6 = 0000 0110
73/2 = 36 R 1 Least significant
36/2 = 18 R 0
18/2 = 9 R 0
9/2 = 4 R 1
4/2 = 2 R 0
2/2 = 1 R 0
1/2 = 0 R 1
73 = 01001001
Add the two binary numbers together
0100 1001 + 0000 0110 = 0100 1111
Take 1s complement (invert each bit)
1011 0000
Take 2s complement (add 1)
1011 0001
convert back to decimal using place value
-128 + 0 + 32 + 16 + 0 + 0 + 0 + 1 = -79