first use slope formula, y2 - y1 / x2 - x1 on the points, 4-2 / 4-3, the slope is 2. then plug this into the equation y = mx + b where m is the slope. use one of the points to solve for b, i will use (3, 2). 2 = 2(3) + b. Solving for b, you would get b = -4. so now you have everything you need, the equation would be y = 2x - 4