I believe that the answer is 1/5. I hope that this answer helps!<span />
Answer:
x^2 - 8xy + 3y^2 - 2
Step-by-step explanation:
(-8xy + 2x^2 + 3y^2) - unknown = x^2 + 2
- unknown = x^2 + 2 + 8xy - 2x^2 - 3y^2
- unknown = -x^2 + 8xy - 3y^2 + 2
Unknown = x^2 - 8xy + 3y^2 - 2
Check:
(-8xy + 2x^2 + 3y^2) - (x^2 - 8xy + 3y^2 - 2)
= -8xy + 2x^2 + 3y^2 - x^2 + 8xy - 3y^2 + 2
= -8xy + 8xy + 2x^2 - x^2 + 3y^2 - 3y^2 + 2
= x^2 + 2
3x + 9 = 90
3x = 90 - 9 = 81
x = 81/3 = 27
x = 27
