Let's solve each problem step by step from the worksheet titled
"Adding, Subtracting, Multiplying Complex Numbers - Independent Practice".
We'll go through each problem and simplify using the rules of complex numbers. Remember:
- A complex number is in the form $ a + bi $, where $ a $ and $ b $ are real numbers, and $ i $ is the imaginary unit with $ i^2 = -1 $.
- To add/subtract: Combine like terms (real parts and imaginary parts).
- To multiply: Use distributive property (FOIL), remembering $ i^2 = -1 $.
---
Problem 1: $ (4 + 8i) + (9 + 16i) $
Add real parts and imaginary parts:
$$
(4 + 9) + (8i + 16i) = 13 + 24i
$$
✔ Answer: $ 13 + 24i $
---
Problem 2: $ 5i(2 + 4i) $
Distribute $ 5i $:
$$
5i \cdot 2 + 5i \cdot 4i = 10i + 20i^2
$$
Now replace $ i^2 = -1 $:
$$
10i + 20(-1) = 10i - 20 = -20 + 10i
$$
✔ Answer: $ -20 + 10i $
---
Problem 3: $ (3 + 13i) - (14 + 5i) $
Subtract real and imaginary parts:
$$
(3 - 14) + (13i - 5i) = -11 + 8i
$$
✔ Answer: $ -11 + 8i $
---
Problem 4: $ 6(2 + 8i) $
Distribute 6:
$$
6 \cdot 2 + 6 \cdot 8i = 12 + 48i
$$
✔ Answer: $ 12 + 48i $
---
Problem 5: $ (15 - 13i) - (18 + 2i) $
Subtract:
$$
(15 - 18) + (-13i - 2i) = -3 - 15i
$$
✔ Answer: $ -3 - 15i $
---
Problem 6: $ (7 + 22i) + (15 + 4i) $
Add:
$$
(7 + 15) + (22i + 4i) = 22 + 26i
$$
✔ Answer: $ 22 + 26i $
---
Problem 7: $ (2 + 15i) + (5 + 5i) $
Add:
$$
(2 + 5) + (15i + 5i) = 7 + 20i
$$
✔ Answer: $ 7 + 20i $
---
Problem 8: $ 5i(7 + 8i) $
Distribute:
$$
5i \cdot 7 + 5i \cdot 8i = 35i + 40i^2
$$
Replace $ i^2 = -1 $:
$$
35i + 40(-1) = 35i - 40 = -40 + 35i
$$
✔ Answer: $ -40 + 35i $
---
Problem 9: $ (7 + 8i) + (8 + 4i) $
Add:
$$
(7 + 8) + (8i + 4i) = 15 + 12i
$$
✔ Answer: $ 15 + 12i $
---
Problem 10: $ (8 - 17i) - (13 - 5i) $
Subtract:
$$
(8 - 13) + (-17i - (-5i)) = -5 + (-17i + 5i) = -5 - 12i
$$
✔ Answer: $ -5 - 12i $
---
✔ Final Answers:
1. $ 13 + 24i $
2. $ -20 + 10i $
3. $ -11 + 8i $
4. $ 12 + 48i $
5. $ -3 - 15i $
6. $ 22 + 26i $
7. $ 7 + 20i $
8. $ -40 + 35i $
9. $ 15 + 12i $
10. $ -5 - 12i $
Let me know if you'd like these checked or explained further!
Parent Tip: Review the logic above to help your child master the concept of simplifying imaginary numbers worksheet.