Question

Find the equation of the linear function represented by the table below in slope-intercept form.

x y
minus, 2−2 77
22 minus, 13−13
66 minus, 33−33
1010 minus, 53−53

Answer 1

y = -5x -3

Explanation:

You want the slope-intercept equation that matches the points (-2, 7), (2, -13), (6, -33), (10, -53).

Slope

The slope of the line can be found using ...

m = (y2 -y1)/(x2 -x1)

m = (-13 -7)/(2 -(-2)) = -20/4 = -5

Intercept

The y-intercept can be found using ...

b = y -mx

b = 7 -(-5)(-2) = -3

Slope-intercept form

The slope-intercept equation is ...

y = mx +b . . . . . . . slope = m, y-intercept = b

y = -5x -3

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Additional comment

The result can be checked easily using the linear regression function of a calculator or spreadsheet. As we see above, we only need two points to define the line.

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