if $f(x)=2x^{2}+1$, what is $f(x)$ when $x = 3$?\n1\n7\n13\n19

Explanation:

Step1: Substitute x value

Substitute (x = 3) into (f(x)=2x^{2}+1), we get (f(3)=2\times3^{2}+1).

Step2: Calculate exponent

First calculate (3^{2}=9), so (f(3)=2\times9 + 1).

Step3: Calculate multiplication

Then (2\times9=18), so (f(3)=18 + 1).

Step4: Calculate addition

Finally, (18+1 = 19).

Answer:

D. 19