Answer:
-12
Step-by-step explanation:
Use synthetic division to find the remainder:
a + 2 yields the synthetic division divisor -2. The four coefficients of a^3 - 4 are {1, 0, 0, -4}. Setting up synthetic division results in:
-2 / 1 0 0 -4
-2 4 -8
-------------------------
1 -2 4 -12
The remainder is -12. This is also the value of a^3 - 4 when a = -2.