Answer:
The linear function that models the charge for hiring the technician for x hours is y=45*x + 55
Step-by-step explanation:
The linear function is defined by the equation
f(x) = mx + b or y = mx + b
where m is the slope of the line and b is the y-intercept.
In this case you want to represent a linear function that models the charge for hiring the technician for x hours, that is, y represents the charge for hiring the technician and x the number of hours.
Given the coordinates of two points (x1, y1) and (x2, y2), you can determine the equation of the line first knowing the slope m by:
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
In this case, the points are:
So:
[tex]m=\frac{370-190}{7-3}[/tex]
Solving:
m=45
To obtain the value of b, once you have replaced the value of m in the equation, you must substitute the values of x and y for the values of the coordinates of one of the points, and solve for b to obtain its value. In this case you replace the value of point 1:
[tex]y=45*x+b[/tex]
[tex]190=45*3+b[/tex]
And you get:
190= 135 + b
190 - 135= b
55= b
So, the linear function that models the charge for hiring the technician for x hours is y=45*x + 55
We want to find a linear equation that models the charge for hiring the technician for x hours.
The correct option is D, the equation is:
y = ($45/h)*x + $55
We know that a general linear equation is written as:
y = a*x + b
where a is the slope and b is the y-intercept.
If the line passes through two points (x₁, y₁) and (x₂, y₂) then the slope can be written as:
[tex]a = \frac{y_2 - y_1}{x_2 - x_1}[/tex]
Here we have two points, one given by:
(3 hours, $190)
The other given by:
(7 hours, $370)
Then the slope is given by:
[tex]a = \frac{\$ 370 - \$ 190}{7h - 3h} = \$ 45/h[/tex]
This means that he charges $45 per hour.
Replacing that in the general equation we get:
y = ($45/h)*x + b
To find the value of b, we use the fact that he charges $190 for 3 hours, then we can solve:
$190 = ($45/h)*3h + b
$190 = $135 + b
$190 - $135 = b = $55
Then the equation is:
y = ($45/h)*x + $55
So the correct option is D.
If you want to learn more, you can read:
https://brainly.com/question/2263981
