First, find the slope using the equation m = (y2 - y1)/(x2 - x1) and then once you have it, put the slope into the equation for a line y = mx + b. So now, all that’s left is finding b so use one of the coordinate given to you and plug them in for x and y and solve for b. Once you find b, you just plug it into the equation with m and then you have your equation.