To find the value of the function f(x) at x = 3, we need to substitute 3 into the function.
The function is defined as:
f(x) = 5x² + 20
Now, we will replace x with 3:
f(3) = 5(3)² + 20
Calculating (3)² gives us:
3² = 9
Now we substitute this back into the equation:
f(3) = 5(9) + 20
Next, we calculate 5 times 9:
5 * 9 = 45
Now we can add 20 to that result:
45 + 20 = 65
Therefore, the final answer is:
f(3) = 65
So, when x = 3, f(x) evaluates to 65.