Perform the indicated multiplications

Question

(2+i)(-3-3i)                         and                            (2-4i)(1-5i)

Answer 1

It's a straightforward binomial expansion, with the one trick being that i² = -1.

 

So (2+i)(-3 - 3i) = -6 - 3i - 6i - 3i² = -6 -9i - 3(-1) = -6 - 9i + 3 = -3 - 9i

 

And (2 - 4i)(1 - 5i) = 2 - 4i - 10i + 20i² = 2 - 14i + 20(-1) = -18 - 14i

Answer 2

-3i^2-3i-6 and 20i^2-14i+2