Question

given the following polynomial function, evaluate f(3). f(x)=x^{2}+4x f(3)=32 f(3)= - 3 f(3)=21 f(3)=5

Explanation:

Step1: Substitute x = 3

Substitute \(x = 3\) into \(f(x)=x^{2}+4x\), we get \(f(3)=3^{2}+4\times3\).

Step2: Calculate powers

Calculate \(3^{2}=9\), so \(f(3)=9 + 4\times3\).

Step3: Calculate multiplication

Calculate \(4\times3 = 12\), so \(f(3)=9+12\).

Step4: Calculate sum

Calculate \(9 + 12=21\).

Answer:

C. \(f(3)=21\)