4. You have the following function:
f(x) = x^2 + 6
In order to determine if the prevous function is even, odd or neither, remind that you have odd and even function for the following cases:
f(-x) = f(x) even
f(-x) = -f(x) odd
Then, if you replace x by -x into f(x), you get:
f(-x) = (-x)^2 + 6
= x^2 + 6
= f(x)
Then, in this case f(-x) = f(x), hence, the function is even
