The first thing you must do is find the slope.
Let m = slope
m = (8-3)/(4-2)
m = 5/2....This is the slope.
We now use the point-slope formula and one of the points given to you to find your equation of the line passing through the given two points..
I will use point A(2,3) but you can use point B if you want to.
y - y1 = m(x-x1)....This is the point-slope formula.
We now plug and chug.
y - 3 = (5/2)(x - 2)
y - 3 = (5/2)(x) - 5
y = (5/2)(x) - 5 + 3
y = (5/2)(x) - 2....This is your equation of the line that passes through points A and B.
The slope is 5/2 and the y-intercept is 3.
I hope this helps.