From a77d7c0cf6c2841ddeb98456a6390bea1c2d8cb1 Mon Sep 17 00:00:00 2001
From: Tammy Lee <23483781+tttlee@users.noreply.github.com>
Date: Sat, 13 Apr 2019 06:21:42 -0700
Subject: [PATCH] Added explanation for single y intercept (#31540)

---
 guide/english/mathematics/x-and-y-intercepts/index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/guide/english/mathematics/x-and-y-intercepts/index.md b/guide/english/mathematics/x-and-y-intercepts/index.md
index 9eff18dfdb..6e839bab51 100644
--- a/guide/english/mathematics/x-and-y-intercepts/index.md
+++ b/guide/english/mathematics/x-and-y-intercepts/index.md
@@ -7,7 +7,7 @@ The X intercept(s) are the point(s) on the X axis where the graph of the functio
 
 The Y intercept is the point at which the graph of the function crosses the Y axis. It occurs where ```x = 0```. 
 
-A function can have multiple X intercepts, but can only have a single Y intercept. 
+A function can have multiple X intercepts, but can only have a single Y intercept. Why is only a single Y intercept allowed? By definition, a function can only have one output, y, for each unique input, x. Thus, a graph would violate this definition if ```x = 0``` produced more than one output, y.
 
 To find the X intercept(s), set ```y = 0``` and solve the equation for x.