In this question, we have to write the set of points from -6 to 3 but excluding -2 and 3 as a union of intervals .
For union, we use U.
For the points that we have to exclude , we put parenthesis on there side that is ().
Therefore the required interval form is

As we see that () are used with -2 and 3 . And that's the required interval form .
When you are given a point (x1,y1) and slope m the equation is
y-y1=m(x-x1)
given
slope=7
(x,y)
(3,22)
x1=3
y1=22
y-22=7(x-3) is the equation or
y=7x+1