Question

What should be subtracted from -8xy + 2x^2 + 3y^2 to get x^2 + 2

Answer 1

x^2 - 8xy + 3y^2 - 2

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