Final answer:
The simplified expression is y^2 + 32.
Step-by-step explanation:
The given expression is 4y^2 + 7 - 3y^2 + 25.
To solve this expression, we need to combine like terms. The terms 4y^2 and -3y^2 have the same variable raised to the same exponent, so we can combine them to get y^2. Similarly, we can combine the constants 7 and 25 to get 32.
Therefore, the simplified expression is y^2 + 32.