Class notes Math 1111

College Algebra 1111:
Homework 2.4 Complex Numbers
Columbus Technical College



1. (4+ 6i) + (- 5 - 4i) 2. (5 + 3i) + (-8 +i)
(4 – 5) + (6 – 4) i (5 – 8) + (3 + 1) i
-1 + 2i -3 + 4i
Collect like terms and then calculate

3. ( -7 – i) – ( -4 + 3i) 4. (7 – 3i) – (7 + 7i)
(-7 – i) + (4 – 3i) (7 – 3i) + (-7 – 7i)
( -7 + 4) + (-1 – 3) i -10i
-3 – 4i
Distribute and then follow the usual steps

5. (5 – 19i) + (4 + 11i) 6. (5 – 19i) – (4 + 11i)
(5 + 4) + (-19 + 11) i (5– 19i) + (-4 – 11i)
9 – 8i (5 – 4) + (-19 – 11) i
1– 30i

7. (14 - √ -4) + (-22 + √ -121) 8. (14 - √ -4) – (-22 + √ -121)
(14 – 2i) + (-22 + 11i) (14 – 2i) – (-22 + 11i)
(14 – 22) + (-2 + 11) i (14 – 2i) + (22 – 11i)
-8 +9i (14 + 22) + (-2 – 11) i
Solve the square root has if it was not 36 – 13i
negative and then add i at the end.

9. (21 – 2i) – (-18 – 16i) 10. (-2i) (7i)
(21 – 2i) + (18 + 16i) -14 × -1
(21 + 18) + (-2 + 16) i 14
39 + 14i i equal -1