I need help. My professor said Im missing something in the below problem:

During the 1998-1999 Little League season, the Tigers played 57 games. They lost 21 more games than they won. How many games did they win that season?

Here is my answer. What is my mistake here?

We will need to establish values to help solve

Let's make the number of games won = X

The games that were lost= Y

We will havex+y = 57.57 represents the total amount of games played. The Tigers lost 21 more games than they won.loss isy =x+21

x + (21 + x) = 57

2 x + 21 = 57Let's subtract 21 from right of the plus sign.

-21-21

The result will give us:

2x = 36

Now we need to solve for x by dividing both sides by 2 and that leaves us with :

x = 18

Let's solve for y by substituting 18 into the equation where you see the x.

x +y=57

18 + (21 +18) = 57

18+39 =57

The Tigers won 18 games and lost 39