14.
Subtracting a negative number is like adding a positive number. So, you can change 9 - (-5) into 9 + 5, which is much simpler. Then, just add to get 14.
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Answer:
(B)
Step-by-step explanation:
Volume of fluid in the tank =1000 gallons
Initial Amount of Salt in the tank, A(0)= 30 pounds
Incoming brine solution of concentration 2 pounds of salt per gallon is pumped in at a rate of 4 gallons per minute.
Rate In=(concentration of salt in inflow)(input rate of brine)

The resulting mixture is pumped out at the same rate, therefore:
Rate Out =(concentration of salt in outflow)(output rate of brine)

Therefore:
The rate of change of amount of salt in the tank, 

 
        
             
        
        
        
The possible lengths of the garden would be all of the common factors of 1200.
1 , 1200
2 , 600
3 , 400
4 , 300
5 , 240
6 , 200
7 , 171.43
8 , 150
9 ,  133.33
10 . 120
11 . 109.09
12. 100
13. 92.31
14. 85.71
15. 80
16. 75
17. 70.59
18. 66.67
19. 63.15
20. 60
And so on. (all of the above are in pairs)
        
                    
             
        
        
        
Splitting up the interval [0, 6] into 6 subintervals means we have
![[0,1]\cup[1,2]\cup[2,3]\cup\cdots\cup[5,6]](https://tex.z-dn.net/?f=%5B0%2C1%5D%5Ccup%5B1%2C2%5D%5Ccup%5B2%2C3%5D%5Ccup%5Ccdots%5Ccup%5B5%2C6%5D)
and the respective midpoints are 

. We can write these sequentially as 

 where 

.
So the integral is approximately

Recall that



so our sum becomes

 
 
        
        
        
Follow PEMDAS.
You would first do your distributive property which is, -5(z+2). You would multiply -5 to z and -5 to 2 which will give you -5z + -10.
so now you have 2z-5z+ -10= -8 - 2z. Now you must isolate the variable. So subtract -8 to -10 which will give you -18. 
Now you have the equation 2z-5z-18=-2z
Now combine like terms. 2z-5z= -3z
Now you have the equation -3z-18=-2z
Now you must move the -3z to the other side of the equal sign by adding the opposite which is +3z to -2z which will give you +1z
Now you have -18= 1z
Now you divide. -18 divided by 1 is -18.
So your final answer will be -18=z