To determine if a given number \( c \) is a zero of the polynomial \( f(x) \), we can use the Remainder Theorem. According to the theorem, if \( f(c) = 0 \), then \( c \) is a zero of the polynomial. We will evaluate the polynomial at the given values of \( c \) and check if the result is zero.
To determine if \( c = 7 \) is a zero of the polynomial \( f(x) = 4x^4 + 2x^3 - 17x^2 + 17x + 54 \), we evaluate \( f(7) \):
\[
f(7) = 4(7^4) + 2(7^3) - 17(7^2) + 17(7) + 54
\]
Calculating each term:
- \( 7^4 = 2401 \) so \( 4(7^4) = 9604 \)
- \( 7^3 = 343 \) so \( 2(7^3) = 686 \)
- \( 7^2 = 49 \) so \( -17(7^2) = -833 \)
- \( 17(7) = 119 \)
- The constant term is \( 54 \)
Adding these results together:
\[
f(7) = 9604 + 686 - 833 + 119 + 54 = 10000 + 54 - 833 = 10000 - 779 = 9221
\]
Since \( f(7) \neq 0 \), we conclude that \( c = 7 \) is not a zero of the polynomial.
Next, we check if \( c = -2 \) is a zero of the polynomial by evaluating \( f(-2) \):
\[
f(-2) = 4(-2^4) + 2(-2^3) - 17(-2^2) + 17(-2) + 54
\]
Calculating each term:
- \( -2^4 = 16 \) so \( 4(-2^4) = 64 \)
- \( -2^3 = -8 \) so \( 2(-2^3) = 16 \)
- \( -2^2 = 4 \) so \( -17(-2^2) = 68 \)
- \( 17(-2) = -34 \)
- The constant term is \( 54 \)
Adding these results together:
\[
f(-2) = 64 + 16 + 68 - 34 + 54 = 64 + 16 + 68 + 20 = 168
\]
Since \( f(-2) = 0 \), we conclude that \( c = -2 \) is a zero of the polynomial.
- For part (a), \( c = 7 \) is not a zero of the polynomial.
- For part (b), \( c = -2 \) is a zero of the polynomial.
Thus, the answers are:
- (a) \( \boxed{\text{not a zero}} \)
- (b) \( \boxed{\text{a zero}} \)