Answer :

[tex](m^{-2})^5=m^{-2\cdot5}=m^{-10}[/tex]

[tex]x^2+3x-10=\\ x^2+5x-2x-10=\\ x(x+5)-2(x+5)=\\ (x-2)(x+5)[/tex]
(m*-2)*5 simplifies to m*-10. 

This is because when you have a number with an exponent to an exponent, you multiply the exponents.