## Intermediate Algebra (6th Edition)

-4$x^{2}$ + 10$y^{2}$
(4$x^{2}$ - 6xy + 9$y^{2}$) - (8$x^{2}$ - 6xy - $y^{2}$) = 4$x^{2}$ - 6xy + 9$y^{2}$ - 8$x^{2}$ + 6xy + $y^{2}$ = -4$x^{2}$ + 10$y^{2}$