(-5,-7) and ( -3,-8)
x(1) = - 5 , y(1) = - 7
x(2) = - 3 , y(2) = - 8
M = (( Y(2) - Y(1))/((X(2) - X(1))
m = (- 8 - ( - 7))/( - 3 - ( - 5))
m = ( - 8 + 7)/(- 3 + 5)
m = - 1/2
Y - Y(1) = M(X - X(1))
y - ( - 7) = - 1/2 (x - (- 5 ))
y + 7 = - x/2 - 5/2
y = - x/2 -5/2 - 7
y = - x/2 - 5/2 - 7*2/2
y = - x/2 - 19/2