Question

(-8a^2+ab-8b^2)-(-9a^2-ab+7b^2)​

Answer 1

$( - {8a}^{2} + ab - {8b}^{2} ) - ( - {9a}^{2} - ab + 7 {b}^{2} ) = - {8a}^{2} + ab - {8b}^{2} + {9a}^{2} + ab - 7 {b}^{2} = {a}^{2} + 2ab - 15 {b}^{2}$

Answer 2

(-8a² + ab - 8b²) - ( -9a² - ab + 7b²) = -8a² + ab - 8b² + 9a² + ab - 7b² = a² + 2ab - 15b²