Question

Given the function f(x) = 5x2 - 9x + 18, find f(3).

A) f(3) = 31
B) f(3) = 36
B) f(3) = 49
D) f(3) = 85

Answer 1

f(3) = 36

Explanation:

To evaluate f(3) substitute x = 3 into f(x), that is

f(3) = 5(3)² - 9(3) + 18 = 5(9) - 27 + 18 = 45 - 27 + 18 = 36

Answer 2

Answer: f(3)= 36

Explanation:

F(x)=5x2-9x+18

Looking at this equation;

F(x)=f(3)

I.e substitute

X=3

Substitute for x=3 in f(x)

F(3)= 5(3)2-9(3)+18

F(3)= 5(9)-27+18

F(3)= 45-27+18

F(3)= 36

So final answer is

F(3)= 36