Fixed alignment in 2-B-1

Author: blulightspecial

_problems/unit-02/B-pmf-properties/1.md

@@ -15,10 +15,10 @@ When we apply this to our specific equation we get the following:
 
 \\[
     \begin{align}
-    1 &= \sum_{x \in 1,2,5} f(x)
-      &= f(1) + f(2) + f(5)
-      &= c + c + 2c
-      &= 4c
+    1 &= \sum_{x \in 1,2,5} f(x)\\\\\
+      &= f(1) + f(2) + f(5)\\\\\
+      &= c + c + 2c\\\\\
+      &= 4c\\\\\
     c &= 1/4 = 0.25
     \end{align}
 \\]