Interval notation uses parenthesis ( or ) for points that are not included in the function (open circle) and brackets [ or ] for points that are included in the function (filled in circle).
Remember that the domain for a function is the range of x-values in a function.
Interval notation includes the numbers at the each end of a continuous function. For function F, the leftmost x-value is 0. The rightmost x-value is 8. Both points at x = 0 and x = 8 are included in the function (filled in circles), so you would use the brackets. The entire function is continuous between those two points.
That means the interval notation for the domain of F is: [0, 8]
We want the equation of this line in the point-slope form y - k = m(x - h).
We are given two points (8, -7) and (-9, 7), and may arbitrarily choose one of them to serve as the point (h, k) in the point-slope form shown above. Then the other point is represented by (x, y) in the point slope form shown above:
Let (h, k) be 8, -7) and let (x, y) be (-9, 7). Then, y - k = m(x - h) becomes:
7 - (-7) = m(-9 - 8), so that 14 = m(-17), and the slope is thus m = -14/17
The desired equation is then y + 7 = (-14/17)(x - 8) (which is in point-slope form).
Another way to get this result would be to find m in the usual way:
rise 14
m = ------------- = --------- = -14/17 (same as before).