Respuesta :

Answer:

a) = 7x² + 4y²

b) = 3x + 7xy - 7

Step-by-step explanation:

a) = (9 - 2) x² + (-3 + 7) y²

= 7x² + 4y²

b) = (8 - 5) x + (3 + 4) xy - 7

= 3x + 7xy - 7