Verified answer

Plugging f(x) = x^1 + x^2 + x^3 + x^4 + x^5 + x^6 into Excel for every x between -2 & 5 gives you the following answers:

f(-2) = 42

f(-1) = 0

f(0) = 0

f(1) = 6

f(2) = 126

f(3) = 1092

f(4) = 5460

f(5) = 19530

After that, the numbers continue to increase exponentially. Your answer is two: f(-2), f(1).