Its pretty hard need someone to solve it (triganomotry)

-6+ -6- -2
Adding a negative is the same as subtracting a positive.
-6 - 6 - -2
Subtracting a negative is the same as adding a positive.
-6 - 6 + 2
Subtracting a number from a negative number is like adding the positive numbers, just remember to put the negative sign in front of the number.
-12 + 2
Adding a positive number to a negative number is like subtracting a positive from another positive, but don't forget the negative sign when you're done.
-12 +2 = -10