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The graph shows the height y (in feet) of an elevator x seconds after it begins to ascend. Write an equation of the line. Then find the speed of the elevator.

The graph shows the height y (in feet) of an elevator x seconds after it begins to-example-1
User William Moore
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1 Answer

7 votes
7 votes

Answer:

y = 3x + 9

Explanation:

Since this is a linear equation we can write this in slope intercept form given the two points (0,9) and (3,18)

The equation of a line in slope-intercept form is y = mx + b where m = slope and b = y-intercept

The slope is given by rise/run where rise is the difference in the y values for two points and the run is the difference in the corresponding x values for both points

Rise = 18 - 9 = 9

Run = 3 - 0 = 3

Slope m = 9/3 = 3

The y-intercept which is the y-value where the line crosses the y-axis. This is also the y-value when x = 0

From the graph we can see the line crosses the y axis at x=0, y = 9 so b = 9

The equation of the line is
y = 3x + 9

User Aatwork
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