Jenny has 280 meters of fencing and wishes to form three sides of a rectangular field. the fourth side borders a river and will not need fencing. as shown below, one of the sides has length x (in meters). find a function that gives the area a(x) of the field in terms of x

a(x) = x*y = x*(280 - 2x) square meters

Step-by-step explanation:

In the figure attached, a plot of the problem is shown. Let's call y the length of the side that parallels the river

The perimeter that the fence cover is:

2x + y =  280 meters

Isolating y:

y =  280 meters - 2x

The area of the field is:

a(x) = x*y = x*(280 - 2x) square meters

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

is only a line? i think so