Answer:
? = 4
Explanation:
2/13 + ?/13 = 6/13 (Given)
-2/13 -2/13 (Isolate the unknown through subtraction)
?/13 = 6/13 - 2/13
?/13 = 4/13 (Combine like terms)
? = 4
Because the demoninators are the same, the unknown value can be found using isolation techniques. To find the unknown, subtract 2/13 from both sides. This eliminates the 2/13 from the right side while obeying the rule that states that what is done to one side must to done to the other. This leaves the ?/13 by itself on the right and 4/13 on the left. Again, because the demoninators are identical, the unknown value must be 4.