Step-by-step explanation:
If any polynomial function f(x) = ax^4 + bx^3 + cx^2 + dx + e is divided by (x + m), then the remainder obtained is f(-m).
So if polynomial x^4 + k is divided by x + 2 then remainder is,

But the remainder is 3. So equation for k is,

Simplify the equation for k.

So value of k is -13.
Answer: -13