Question

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

Answer 1

21 + 12i

Explanation:

Given

(3 - 4i)(1 + 5i) - (2 - i) ← expand the product of factors using FOIL

= 3 + 11i - 20i² - 2 + i ( note i² = - 1 )

= 3 + 11i + 20 - 2 + i ← collect like terms

= 21 + 12i

Answer 2

The answer is

21 + 12i

Explanation:

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

Expand the terms in the bracket first

That's

3 + 15i - 4i - 20i² - ( 2 - i)

Remove the bracket

3 + 15i - 4i - 20i² - 2 + i

But i² = - 1

Group like terms

- 20(-1) + 15i - 4i + i + 3 - 2

15i - 4i + i + 20 + 3 - 2

Simplify

We have the final answer as

21 + 12i

Hope this helps you