Question

Simplify the expression (3 - 4i)(1 + 5i) - (2 - i). Show your work

Answer 1

Answer: 12i + 21

Step-by-step explanation:

You want to apply foil to the first two terms.

1. 3 x 1 = 3
2. 5i x 3 = 15i
3. -4i x 1 = -4i
4. -4i x 5i = -20i^2

You get 3 + 11i - 20i^2. i is equal to the square root of -1, so when you square it, you will get -1. Then do -1 x -20 to get +20

So far you have (11i + 23) - (-i + 2).

1. 11i + i = 12i
2. 23 - 2 = 21

Im 99% sure the answer is 12i + 21