subtract(3x+8xy-9)-(-8+9xy+6)?

= (3x + 8xy - 9) - (- 8 + 9xy + 6)
= 3x + 8xy - 9 + 8 - 9xy - 6
= 3x - xy - 7

Answer: 3x - xy - 7

(3x + 8xy - 9) - (-8 + 9xy + 6)
= 3x + 8xy - 9 + 8 - 9xy - 6
= 3x + 8xy - 9xy - 9 + 8 - 6
= 3x - xy - 7

3x + 8xy - 9 + 8 -9xy - 6
3x -xy - 7 this is the ans if u want to go further to find x y values so can go easily

Firstly I'll assume you meant 8x for the first variable in the second equation

11x - xy - 15

or if not

3x - xy - 7

3x - xy - 7