Answer:
- 7x^2 + 3xy - 9y
Step-by-step explanation:
(2xy- 4x^2) - (9y + 3x^2 - xy)
Add the second polynomial:
Change all the signs in the second polynomial because it has a negative sign before the parentheses.
= 2xy - 4x^2 - 9y - 3x^2 + xy
Combine like terms:
(-4x^2 - 3x^2) + (2xy + xy) - 9y
= -7x^2 + 3xy - 9y
