Answer:
4 + 5i
Explanation:
To calculate this you have to combine the like terms until they cannot be combined any further:
7 + 10i + 4 - 10i - (7 - 5i)
11 + 0i - 7 - 5i
7 & 4 are liked terms so add them together + subtract 10i and 10i
4 + 5i <--- Final answer
Hope this helps!