Question

Consider the function f(x) = x2 + 3x − 7. Find the value of f(x) when x = 3 and select the correct answer below.

5
8
11
18

Answer 1

When x = 3, the function f(x) = x² + 3x − 7 has a value of 11.

To find the value of the function when we are given a certain value of x, we need to substitute the value of x (in this case 3) wherever we see it in the function, and then simplify the function like always.

In this function, x appears 2 times, in x² and 3x. Substituting x = 3, we get:

f(x) = (3)² + 3(3) - 7

Now we simplify using the order of operations. Exponents:

f(x) = 9 + 3(3) - 7

Multiplication

f(x) = 9 + 9 - 7

Addition and subtraction

f(x) = 11

That means that f(x) = 11 when x = 3.

Answer 2

= 11

Step-by-step explanation

f(x) = x² + 3x- 7

To get the value of f(x) when x = 3, we substitute x with 3 in the function f(x).

f(x) = x² + 3x- 7

= 3² + (3×3) -7

= 9 + 9 - 7

= 11