Verified answer

Answer:

x² + 3xy - 2y²

Step-by-step explanation:

We can simplify the given expression by first removing the brackets and then combining like terms.

(2x²+3xy-3y²)-(x²-y²)

= 2x² + 3xy - 3y² - x² + y²  [distributing negative sign in the second bracket]

= (2x² - x²) + (3xy) + (-3y² + y²)   [grouping like terms]

= x² + 3xy - 2y²

Therefore, the simplified form of the given expression is x² + 3xy - 2y².