Complex Numbers

1. Simplify .

 -4

 4

 4i

2. Simplify .

  -9

  -9i

  9i

3. Use the powers of i to simplify i¹⁴.

  i

  1

  -1

4. Use the powers of i to simplify i⁶⁴.

 i

 1

 -1

5. Use the powers of i to simplify i ⁹.

 i

 1

 -1

6. Solve for x and y such that the statement  5 + yi = x + 7i   is true.

 x = 5, y = 7

 x = 7, y = 5

 Not enough information.

7. Add (3 + 2i) + (7 + 5i).

 11 + 29i

 -4 - 3i

 10 + 7i

8. Subtract (5 + 2i) - (1 - 4i).

 4 + 6i

 4 - 2i

 6 - 2i

9. Multiply 4i * (9 + 2i).

 -8 + 36i

 8 + 36i

 36 + 8i

10. Multiply (2i - 1) (3i + 4).

 -6 + 5i - 4

 -10 + 5i

 6i² + 5i - 4

11. Divide .

 -2 + 4i

 2 + 4i

 -2 - 4i

12. Divide .

 2

 -2

 Not enough information.