The diffrence of two numbers is 3. their sum is 13. find the two numbers

To solve, I used 'x' and 'y' to represent the two unknown numbers and combined them as the problem said. Because one number minus the other is 3, I wrote x - y = 3. Because the two numbers add to 13, I wrote x + y = 13. I then wanted to get a variable by itself in order to solve. Then, I set the two new problems equal because they both equal the same thing, in this case, 'x'. Once I found 'y', I substituted that value in for itself and solved for 'x'.

x - y = 3
x = 3 + y

x + y = 13
x = 13 - y

3 + y = 13 - y
   + y         + y
3 + 2y = 13
-3           -3
2y = 10
2y / 2 = 10 / 2
y = 5

x = 3 + y
x = 3 + (5)
x = 8

Hope this helps!