Simplify:

-5^2 + 2[64 /(6 - 10)^2] =
-5^2 + 2[64/(-4)^2]=
-5^2 + 2[64/16]=
-25 + 2 [64/16]=
-25 + 2 (4)=
-25 +8
= -17

Is this Corect?

yes, i think that you are correct :)