Set it up as an equation. "A number" is x.
2x-2=x+64
Move all of the x terms to one side by subtracting x from both sides, then add 2 to both sides to isolate x.
X=66
The number is 66
        
             
        
        
        
Answer:
1200÷20=x and x=60
Step-by-step explanation:
   60
x 20
---------
1200
 
        
             
        
        
        
Answer:
The answer is -77
Step-by-step explanation:
Ok, so assuming by x2 you mean x squared, I will solve this. So basically when you have a function, f(-7) would mean that you would have to replace all the x's in the equation with -7. So let's write that out. that would be f(-7) = -7^2 + (-7*4). So now according to PEMDAS, you would solve the exponent first, and -7^2 is equal to -49, because when you solve it you would do -(7^2), which is -(49), which is then -49. So now you have f(-7)= -49+ (4*-7). Solving for (4*-7), you get -28. This leaves you with -49 + (-28), which is -49 - 28. Simplifying that, you get the answer, which is -77. 
 
        
             
        
        
        
Answer:
The exponential function to model the duck population is:
f(n)=415*(1.32)^n, where:
x is the duck population
n is the number of years
Step-by-step explanation:
In order to calculate the duck population you can use the formula to calculate future value:
FV=PV*(1+r)^n
FV=future value
PV=present value
r=rate
n=number of periods of time
In this case, the present value is the initial population of 415 and the rate is 32%. You can replace these values on the formula and the exponential function to model the duck population would be:
f(n)=415*(1+0.32)^n
f(n)=415*(1.32)^n, where:
x is the duck population
n is the number of years