The y-intercept is the point where a function intercepts the y-axis. It can be found by inputting x=0 into a function and simplify to find f(x), which is the y-intercept. When x=0, there is no lateral change, so you are only focusing on the y-axis, meaning the y-intercept will lie on that x-coordinate. Essentially, there is no movement on the x-axis so that you can simply focus on the y-axis and it’s point of interception.