If $3x + 4y = 25$ and $4x + 3y = 24$, what is the value of $y$?

Explanation

1. 01

   Add: $7x + 7y = 49$, so $x + y = 7$.

2. 02

   Subtract the first from the second: $x - y = -1$.

3. 03

   Subtract these two results: $2y = 8$, so $y = 4$ (and $x = 3$).