Answer:
A(x) = x(200-x)
Step-by-step explanation:
400 feet of fencing to enclose a rectangular dog exercise pen means the perimeter of rectangle is 400 feet
If x is length and y is breadth. Perimeter is given by :
P = 2(x+y)
400 = 2(x+y)
⇒ (x+y) = 200 .....(1)
y = 200-x
Area of a rectangle is given by :
A = xy
A(x) = x(200-x)
Hence, the area as a function of length of rectangle is x(200-x).
Answer:
y=2x+6
Step-by-step explanation:
Slope of line is 2
Plug slope and first set of coords into point-slope intercept form
19 feet
convert 2 
into an improper fraction
2 = 
hence the length of the wall is 19 feet
First, conceptually understand what an inverse function is, it makes solving it very intuitive. An inverse function is simply a function which has points (y,x) for every point (x,y) of the parent function. So you are essentially taking all points of the parent function and switching the x and y coordinates for each. Those switched coordinates are produced by the "inverse function".
Mathematically then, finding the inverse function is a matter of solving for x and then switching the variable labels. In this case:
y=2x+1 subtract 1 from both sides
y-1=2x divide both sides by 2
(y-1)/2=x now just switch the labels for the variables...
y=(x-1)/2 so
f^-1(x)=(x-1)/2 is the inverse of f(x)=2x+1
