Answer:
Step-by-step explanation:
No se inglés ando modo amable :v
1.
6 - 2х² = 6 - 2(-8)² = 6 - 2(64) = 6 - 128 = -122
2.

3.

4.

5.

Option 2: 18-5i is the right answer
Step-by-step explanation:
Given

When there is a negative number in radical, a new complex number iota denoted by i is introduced which is equal to 
So we will solve the given expression

Hence,
Option 2: 18-5i is the right answer
Keywords: Iota, complex numbers
Learn more about complex numbers at:
#LearnwithBrainly
Answer:
z=-5
Step-by-step explanation:
-4z=20
divide both sides of the equation by -4
-4z/-4=20/-4
z=-5