Answer:
The correct equation for the trend line is y = 5x + 5
Explanation:
* Lets revise the form of the equation of the line
- The slope intercept form is y = mx + b, where m is the slope of
the line and b is the y-intercept
- In the problem we have a trend line in the scatter-plot
- we cant find the exact value of the slope of the line from the points
in the scatter-plot because the line is best fit to the point, then we
will start with the y-intercept of the line
- From the graph the line intersect the y-axis at point (0 , 5)
∴ The y-intercept is 5
- We have two answers have y- intercept = 5, the first and second
answer, the right answer is one of them
- From the graph try to find two points closed the the line and use
them to find the slope of the line
- There are two points approximately closed to the line at points
(0 , 5) and (-1 , 0)
- Lets use the rule of the slope of a line which passes through points
(x1 , y1) and (x2 , y2)
- The slope of the line = (y2 - y1)/(x2 - x1)
∵ The point (0 , 5) is (x1 , y1) and point (-1 , 0) is (x2 , y2)
∵ x1 = 0 , x2 = -1 and y1 = 5 , y2 = 0
∴ the slope = (0 - 5)/-1 - 0 = -5/-1 = 5
∵ The equation of the line is y = mx + b
∵ m = 5 and b = 5
∴ The equation is y = 5x + 5