Given:
The table of values for Fallon's earnings in terms of Donald's earnings.
To find:
The equation that best represents Fallon's earnings in terms of Donald's earnings.
Solution:
In the given table the x-values are increasing by 5 units and y values increasing by 5 units. It means the rate of change of y with respect to x is constant and the table represents a linear function.
If the graph of a linear function passes through two points, then the equation of linear function is
[tex]y-y_1=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]
Consider any two points from the table. Let the two points are (38,45) and (43, 50). Then, the equation is
[tex]y-45=\dfrac{50-45}{43-38}(x-38)[/tex]
[tex]y-45=\dfrac{5}{5}(x-38)[/tex]
[tex]y-45=1(x-38)[/tex]
[tex]y-45=x-38[/tex]
Adding 45 on both sides, we get
[tex]y=x-38+45[/tex]
[tex]y=x+7[/tex]
Therefore, the correct option is A.
