Subtract 1318−i from 51+13i to get 65174i−77.
To subtract raitonal expressions, both fractions must have the same denominator.
We can create a common denominator by multiplying the first fraction by 13 and the second by 5.
51+13i−1318−i=5⋅13(1+13i)⋅13−13⋅5(18−i)⋅5==6513+169i−6590−5i=6513+169i−(90−5i)==65174i−77