3.3333333 repeating
Take 10 and divide it by 3
We know there are 4 suites the deck can be divided into, and two of the 4 are black. So you divide 2/4, and get 1/2. So the probability that a black card will be chosen is 1/2.
Point slope form is
y-y1=m(x-x1)
where slope=m
and (x1,y1) is a given point
slope=(y2-y1)/(x2-x1)
slope=(6-7)/(-8-(-5))=-1/(-8+5)=-1/-3=1/3
pick any point
(x,y)
(-5,7)
y-7=1/3(x+5) or
y-6=1/3(x+8)