Answer:
m = -63
b = 825
Step-by-step explanation:
First, the slope intercept form of a line is
y = mx + b
where m = slope and b = y-intercept
The slope is also referred to as rise/run ie the ratio of the change in y values to the corresponding change in x values for two points
The y-intercept is y value where the line crosses the y-axis
For two points on the graph (x1, y1) and (x2, y2), the slope is given by the equation :
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
The two indicated points are (4, 699) and (8, 321)
So slope
[tex]m = \dfrac{321 - 699}{8 - 2}[/tex]
[tex]m = \dfrac{-378}{6}[/tex]
[tex]m = -63[/tex]
Therefore the equation of the line is y = mx + b
To find the y-intercept, b, plug in any of these point values into the above equation and solve for b
Let's choose point(8, 321)
We have
y = -63x + b
Substituting for y = 321 and x = 8 gives us
321 = -63(8) + b
Switch sides
-63(8) + b = 321
-504 + b = 321
Add 504 to both sides to get
b = 321 + 504 = 825
So b = 825
