Explanation:
point slope formula: y-y1=m(x-x1)
m= y2-y1/x2-x1
input numbers
so slope:
m=(9--8)/(-7--8)
(-)×(-)=+
(+)×(-)=(-)
so m=17/1
m=17
now point slope
y--8=17(x--8)
y+8=17x+136
to get y alone we have to use opposite operations
y and 8 are adding so we need to subtract on both sides
y+8-8=17x+136-8
y=17x+128