In the case of the two lines you described, the y-intercepts are 1 and 2, meaning that the lines cross the y-axis at the points (0,1) and (0,2), respectively.
To find the equations of the lines, you can use the slope-intercept form of a line, which is written as y = mx + b, where m is the slope of the line and b is the y-intercept. Since the lines intersect at the point (1,3), you can use this point and the y-intercept of each line to find the slope of each line.
For the first line, with y-intercept 1, the slope is given by the formula m = (y2 - y1) / (x2 - x1), where (x1,y1) is the given point (1,3) and (x2,y2) is the y-intercept (0,1). Plugging in these values, we get m = (1 - 3) / (0 - 1) = -2. So the equation of this line is y = -2x + 1.
For the second line, with y-intercept 2, the slope is given by the same formula, using the point (1,3) and the y-intercept (0,2). This gives us m = (2 - 3) / (0 - 1) = -1. So the equation of this line is y = -1x + 2.
Therefore, the equations of the two lines are y = -2x + 1 and y = -1x + 2.