It's the sum of the three masses:

Remove unnecessary parenthesis, and combine like terms
(3+i) + (5-2i)
3+i + 5-2i
8+i
you added 3+5 which is 5 and i-2i which is "i"
hope this helps.
Answer:
25$ per month
Step-by-step explanation:
100$ was saved every 4 months so you divide that by four. You will get 25 which is your rate. (25$ per month)
Addition:<span> Add, Sum, Plus, Increase, Total
Subtraction: </span><span>Subtract, Minus, Less, Difference, Decrease, Take Away, Deduct
<span><span>
Multiplication: Multiply, Product, By, Times, Lots Of
</span></span><span><span>
Division: Divide, Quotient, Goes Into, How Many Times</span></span></span>