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39 votes
Help me out please I don’t understand this and Is been so long seems I don’t go over it .

Help me out please I don’t understand this and Is been so long seems I don’t go over-example-1
User Iamabhaykmr
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1 Answer

22 votes
22 votes

The equation of a line in slope-intercept form, is:


y=mx+b

Where m is the slope of the line and b is the y-intercept.

Notice that the trend line passes through the two yellow points, whose coordinates are:


\begin{gathered} (0,8) \\ (7,3) \end{gathered}

Since the y-intercept is the value at which the line crosses the Y-axis, and we can see that the line crosses the Y-axis precisely at the point (0,8), then the value of the y-intercept is 8. This means that b=8.

On the other hand, the value of the slope can be found using the slope formula:


m=(y_2-y_1)/(x_2-x_1)

Replace the coordinates of the points into the slope formula:


m=(8-3)/(0-7)=(5)/(-7)=-(5)/(7)

Finally, replace m=-5/7 and b=8 to find the equation of the line in slope-intercept form:


y=-(5)/(7)x+8

Therefore, the answer is:


y=-(5)/(7)x+8

User Josh Gust
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