Simple. -2 is equal to exactly -2.
You evaluate it for example {-2} is 2
Evaluate: -7 - 8
evaluate 2x4x2 in the mod 5 system
(2)2
12
Evaluate -6 to the power of 2
1
to evaluate 5 squared you must simply do 5x5. Which equals 25.
6
46
the answer is 5
x = -2