Answer:
more than 200 calls
Suppose number of calls = x
According to plan 1: Total monthly charge is $24
According to plan 2: Fix charge is $16 and $0.04 per call
cost of x's call = $0.04x
and monthly charge according to plan 2 = 0.04x + 16
a)  Plan 1 is more economical than plan 2.
0.04x + 16 > 24
solve it for x
.04x > 8
x > 200
b)   So,  if more than 200 calls are made then Plan 1 is more economical.
Step-by-step explanation:
 
        
             
        
        
        
Answer:

Step-by-step explanation:

 
        
             
        
        
        
Answer:
what are you asking? Because I probably have the answer
 
        
             
        
        
        
Answer:
option D
D. x = 5, y = 2
Step-by-step explanation:
Given in the question two equation,
Equation 1
5.3x + y = 28.5
Equation 2
4.2x + 3.1y = 27.2
rearrange equation 1 in terms of y
y = 28.5 - 5.3x
Substitute the value of y in equation 2
<h3>4.2x + 3.1(28.5 - 5.3x) = 27.2</h3>
4.2x + 88.35 - 16.43x = 27.2
4.2x - 16.43x = 27.2 - 88.35
-12.23x = -61.15
x = 61.15/12.23
x = 5
put value of x in any of the equation
<h3>5.3(5) + y = 28.5</h3>
y = 28.5 - 26.5
y = 2
 
        
             
        
        
        
Answer:
D). 
Step-by-step explanation:
For better clarity let us re write the options 
A).
B).
C).
D).
To express polynomial with mixed variables in standard form, we begin by the highest coefficient of x to the smallest (we place high precedence on the coefficient  x terms)