Answer:
Step-by-step explanation:
hello :
a(x) = 3x - 12 and b(x) = x-9, so
 a[b(x)]=a(x-9) =3(x-9)-12
 a[b(x)]=3x-9-12
 a[b(x)]=3x+21
 
        
             
        
        
        
Given that,
Total cost function, C (x) = 43x + $1850 
The revenue function R (x) = $80x
To find,
The number of units that must be produced and sold to break even.
Solution,
At break even, cost = revenue
43x + $1850 = $80x
Subtract 80x from both sides.
43x + 1850 -80x = $80x -80x
1850 = 80x-43x
37x = 1850
x = 50
So, the required number of units are 50.
 
        
             
        
        
        
The Lewis family and the Perry family each used their sprinklers last summer. The water output rate for the Lewis family's sprinkler was 15 L per hour. The water output rate for the Perry family's sprinkler was 40 L per hour. The families used their sprinklers for a combined total of 65 hours, resulting in a total water output of 1850 L . How long was each sprinkler used
Answer:
Hours of use of sprinkler by Lewis family is 30 hours.
Hours of use of sprinkler by Perry family is 35 hours.
Step-by-step explanation:
Let W = hours of use by Lewis family
65 - W = hours of use by Perry family
Then;
15W + 40*(65 - W) = 1850
15W + 2600 - 40W = 1850
(15 - 40)W = 1850 - 2600
-25W = −750
W = 750/25 = 30
Therefore;
W = 30
65 - W = 65 - 30 = 35
Hence, 
Hours of use by Lewis family is 30 hours.
Hours of use by Perry family is 35 hours.
 
        
             
        
        
        
Four hundred two million seventy-three thousand one hundred eighty in standard form: 402,073,180 would be your answer