The expression (-2 - 6i)-(-2-4i) to a + bi form is 0 - 2i. 
Complete question.
Simplify the expression to a + bi form:
(-2 - 6i)-(-2-4i)
Square root of any negative number are expressed as a complex number. For example i = √-1
Complex numbers are generally written in the format z = x+iy 
Given the expression (-2 - 6i)-(-2-4i)), in expansion:
(-2 - 6i)-(-2-4i)
= -2 - 6i + 2+4i
Collect the like terms
= (-2 + 2) - 6i + 4i 
= 0 - 2i
Therefore the expression (-2 - 6i)-(-2-4i) to a + bi form is 0 - 2i. 
Learn more on complex number here: brainly.com/question/12375854
 
        
             
        
        
        
Answer:
25%
Step-by-step explanation:
25% of 60 is 15 because 15 is 1/4 of 60 and 1/4 is 25%
 
        
                    
             
        
        
        
Answer:
The last choice. The red one 
Step-by-step explanation:
I'm just guessing at this point. But, by the looks of it, red does seem like it would be correct. Again, this is just a guess. So, if it's wrong I'm so sorry. Have a lovely day. 
 
        
             
        
        
        
F(0)= 2* 0 +3 
 =0+3 
f(0)=3