There are so many methods you can use to find the y-intercept of an equation. Here, I will try as much as possible to give the simplest one. In this method, before you can find the y-intercept of an equation, you will need to know the slope of the equation.
The slope is usually calculated using the graph where you divide the coordinate of the y-axis by that of the x-axis. Let's assume the slope of an equation is 3, and it contains the points (1, 5), you can find the y-intercept of this line by using this formula, y = mx + b.
From this equation, b is the y-intercept, x, and y are the two points given in the question. At this point, all we need to do is to substitute each letter for the appropriate value as given in the question so as to find the value of "b." From the equation b=y-mx. b=5 - (3×1)=2. Therefore, the y-intercept of this equation is at y=2.