As a rule , - times - = + and - times + = -
[tex]\begin{gathered} -16m^2n-(-25m^2n)+(-7m^2n\text{ ) } \\ =-16m^2n+25m^2n-7m^2n\text{ ( based on the rule above )} \\ =+9m^2n-7m^2n\text{ ( -16 + 25 = + 9 )} \\ =+2m^2n \end{gathered}[/tex]Therefore the correct answer to the question is 2m squared n
