Answer:
A. Increase by 2
Step-by-step explanation:
Given that a  fitted multiple regression equation is 

This is a multiple regression line with dependent variable y and independent variables x1, x2, x3 and x4
The coefficients of independent variables represent the slope.
In other words the coefficients represent the rate of change of y when xi is changed by 1 unit.
Given that x3 and x4 remain unchanged and x1 increases by 2 and x2 by 2 units
Since slope of x1 is 5, we find for one unit change in x1 we can have 5 units change in y
i.e. for 2 units change in x1, we expect 10 units change in Y
Similarly for 2 units change in x2, we expect -2(4) units change in Y
Put together we have
 change in y
Since positive 2, there is an increase by 2
A. Increase by 2
 
        
             
        
        
        
The answer is:
A solid and a plane.
        
                    
             
        
        
        
Step-by-step explanation:
a1=ar⁰=12 A2=ar¹=-6
a=12 ar=-6
 12r=-6
 r=-6/12
 r=-1/2
a10=ar⁹
 =12*(-1/2)⁹
 =12*(-512)
 =-3/128
S∞ = a1 / (1-r )
 =12/(1-1/2)
 =12*1/2
 =6
 
        
             
        
        
        
Negative numbers aren't considered in any of those categories.