Question 9 of 20

For [tex]f(x) = 2x + 3[/tex] and [tex]g(x) = x^2 - 8[/tex], find [tex](f + g)(x)[/tex].

A. [tex]2x^3 - 18[/tex]
B. [tex]x^2 + 2x - 5[/tex]
C. [tex]2x^2 - 5[/tex]
D. [tex]x^2 + 2x + 71[/tex]



Answer :

To solve for [tex]\((x + g)(x)\)[/tex] given the functions [tex]\(f(x) = 2x + 3\)[/tex] and [tex]\(g(x) = x^2 - 8\)[/tex], we need to follow these steps:

1. Determine [tex]\(g(x)\)[/tex]:

Given [tex]\(g(x) = x^2 - 8\)[/tex].

2. Calculate [tex]\(x + g(x)\)[/tex]:

[tex]\[ x + g(x) = x + (x^2 - 8) \][/tex]
[tex]\[ x + g(x) = x + x^2 - 8 \][/tex]

3. Substitute [tex]\(x + g(x)\)[/tex] into [tex]\(f(x)\)[/tex]:

First, we need to recognize that [tex]\((x + g)(x)\)[/tex] here means we are looking at [tex]\(x + g(x)\)[/tex] and not directly substituting into [tex]\(f(x)\)[/tex]. The expression given as [tex]\((x + g)(x)\)[/tex] simplifies to [tex]\(x + g(x)\)[/tex].

Expanding [tex]\(x + g(x)\)[/tex], we have already found it’s equal to:

[tex]\[ x + x^2 - 8 \][/tex]

Therefore, the function [tex]\((x + g)(x)\)[/tex] simplifies to [tex]\(x + x^2 - 8\)[/tex].

So, from the multiple choices provided:
- B. [tex]\(x^2 + 2x - 5\)[/tex]
- A. [tex]\(2x^3 - 18\)[/tex]
- C. [tex]\(2x^2 - 5\)[/tex]
- D. [tex]\(x^2 + 2x + 71\)[/tex]

The correct form does not match [tex]\(x + x^2 - 8\)[/tex] directly. Let's see which option closely matches by simple expansion and comparison steps:

Let's inspect each option.

For B:
[tex]\[ x^2 + 2x - 5 \][/tex]
This is not the same as [tex]\(x + x^2 - 8\)[/tex].

For A:
[tex]\[ 2x^3 - 18 \][/tex]
This is clearly not the same.

For C:
[tex]\[ 2x^2 - 5 \][/tex]
Again, it doesn’t resemble [tex]\(x + x^2 - 8\)[/tex].

For D:
[tex]\[ x^2 + 2x + 71 \][/tex]
Clearly, it doesn’t resemble [tex]\(x + x^2 - 8\)[/tex].

None match perfectly with [tex]\(x + x^2 - 8\)[/tex], but if you observe carefully, the right transformation function would most translate into,

Given options aren’t exactly fitting solving pattern, so no option clearly defines perfectly.

Thus without a given clear match, simplifies to:
[tex]\( \boxed{x^2 + x - 8} \)[/tex]