Express $$\sqrt{\ -64}$$ in the form ai for some real number a.

Compute (-2i)(-3i)

Compute (-7+2i)+(3+10i).

Note: The brackets are not required here. I only put them there for clarity.

Compute (-7+2i)(3+10i).

Note: In this case, the brackets do need to be there.

Which of the following is the complex conjugate of 11-2i?

Given u=9-3i, compute $$\overline{u}u$$ , where $$\overline{u}$$ is the complex conjugate of u.

Tip: Make a note of your answer because you will need it for the next question.

Hence (i.e. using the answer to the previous question) compute $$\left(9-3i\right)^{-1}$$ .

Tip: Make a note of your answer because you will need it for the next question.

Hence, compute $$\frac{5-3i}{9-3i}$$ .