Question

A line passes through (4, 5) and (8, 9). Which equation best represents the line?

Answer 1

Y=x+1 is the anwser
to the question

Answer 2

Here, Coordinates: (4, 5) & (8, 9)
Calculation of Slope, m = y2-y1 / x2-x1
m = 9-5 / 8-4
m = 4 / 4
m = 1

Now, Take any coordinate: 
y - y1 = m(x - x1)
y - 5 = 1(x - 4)
y - 5 = x - 4
y = x + 1

In short, Your Answer would be: y = x + 1

Hope this helps!