Answer
$= -2x^{2} + 6y^{2}$
Work Step by Step
1. Rewrite the order by grouping like terms next to each other in order to simplify simplification:
$7x^{2} - 2y^{2} - 9x^{2} + 8y^{2}$
$= 7x^{2} - 9x^{2} - 2y^{2} + 8y^{2}$
2. Use the distributive property to simplify
$= x^{2}(7 - 9) - y^{2}(2-8)$
$= x^{2}(-2) - y^{2}(-6)$
$= -2x^{2} + 6y^{2}$
