Answer:
5-46i
Step-by-step explanation:
1. Multiply (10-4i) and (4-5i), I recomnd using foil:
40-50i-16+20i^2 + (-15+20i)
2. Remove the parenthesis around -15+20i
*we can do this since there is a "+":
40-50i-16+20i^2 + (-15)+20
3. Simplify i^2
* i^2 is -1 by textbook defination:
40-50i-16+20(-1) + (-15)+20
4. Simplify
40-50i-16-20 + (-15)+20
6. Combine like terms:
-5-50i-16i+20i
5-46i
And the problem is done
