What’s the equation in slope-intercept form?

You can take any 2 points from the table and calculate the slope, as follows:
                     -2-(-4)        2
m = slope = = = -1/5
                      -5 - 5       -10
The slope-intercept form is    y = mx + b.  You already know m (which is -1/5), and have several points from which to choose to obtain x and y.  Let's use the given point (-2, -1).

Then    -1 = (-1/5)(-2) + b, or   -1 = 2/5 + b.  Solve for b.

-5 = 2 + 5b,  so  5b = -7, and b = -7/5.

The desired equation is     y = (-1/5)x - 7/5.

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