Slope = (5+8)/(8-4) = 13/4
y = mx + b
b= y - mx
b = -8 - (13/4) (4)
b = -8 -13
b = -21
equation
y = 13/4x - 21
The area equation here is:

That means that the area depends on the width measurement of the rectangle.
To graph a quadratic function you have to see if the parabole is positive and the transformations, in this case, are positive and have a multiplication by two, which means that the graphics in x=1 and x=-1 will be y=2
Finally, you can conclude that there, you have a relationship between the area and the width of the rectangle because is a quadratic relationship and the area will increase in a quadratic form according to the increase of the width.
Using decimal multipliers, it is found that the value of x is of 16.67.
<h3>What is a decimal multiplier?</h3>
Increases of a% or decreases of a% re represented by decimal values, as follows:
- The equivalent multiplier for an increase of a% is given by:

- The equivalent multiplier for an decrease of a% is given by:

In this problem:
- The price at the beginning of January was of a.
- Increase of 20% in January, hence
.
- Decrease of 20% in February, hence
.
- Increase of 25% in March, hence
.
- Decrease of x% in April, hence

The price of gasoline at the end of April was the same as it had been at the beginning of January, hence:






The value of x is of 16.67.
To learn more about decimal multipliers, you can take a look at brainly.com/question/24952336