Given that [tex]$f(x)=x^2-6x$[/tex] and [tex]$g(x)=x+3$[/tex], find:

(a) [tex](f+g)(x) = \square[/tex]

(b) [tex](f-g)(x) = \square[/tex]

(c) [tex](fg)(x) = \square[/tex]

(d) [tex]\left(\frac{f}{g}\right)(x) = \square[/tex]



Answer :

Alright, let's solve the problem step-by-step.

Given:
[tex]\( f(x) = x^2 - 6x \)[/tex]
[tex]\( g(x) = x + 3 \)[/tex]

(a) To find [tex]\( (f+g)(x) \)[/tex]:
[tex]\[ (f+g)(x) = f(x) + g(x) = (x^2 - 6x) + (x + 3) \][/tex]
Combine like terms:
[tex]\[ = x^2 - 6x + x + 3 = x^2 - 5x + 3 \][/tex]
So, [tex]\( (f+g)(x) = x^2 - 5x + 3 \)[/tex].

(b) To find [tex]\( (f-g)(x) \)[/tex]:
[tex]\[ (f-g)(x) = f(x) - g(x) = (x^2 - 6x) - (x + 3) \][/tex]
Distribute the negative sign and combine like terms:
[tex]\[ = x^2 - 6x - x - 3 = x^2 - 7x - 3 \][/tex]
So, [tex]\( (f-g)(x) = x^2 - 7x - 3 \)[/tex].

(c) To find [tex]\( (fg)(x) \)[/tex]:
[tex]\[ (fg)(x) = f(x) \cdot g(x) = (x^2 - 6x) \cdot (x + 3) \][/tex]
Distribute [tex]\( (x^2 - 6x) \)[/tex] into [tex]\( (x + 3) \)[/tex]:
[tex]\[ = x^2(x + 3) - 6x(x + 3) \][/tex]
Multiply each term:
[tex]\[ = x^3 + 3x^2 - 6x^2 - 18x = x^3 - 3x^2 - 18x \][/tex]
So, [tex]\( (fg)(x) = (x + 3)(x^2 - 6x) \)[/tex] effectively matches the factored form.

(d) To find [tex]\( \left(\frac{f}{g}\right)(x) \)[/tex]:
[tex]\[ \left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{x^2 - 6x}{x + 3} \][/tex]
So, [tex]\( \left(\frac{f}{g}\right)(x) = \frac{x^2 - 6x}{x + 3} \)[/tex].

Here is a summary of the results:
(a) [tex]\( (f+g)(x) = x^2 - 5x + 3 \)[/tex]
(b) [tex]\( (f-g)(x) = x^2 - 7x - 3 \)[/tex]
(c) [tex]\( (fg)(x) = (x + 3)(x^2 - 6x) \)[/tex]
(d) [tex]\( \left(\frac{f}{g}\right)(x) = \frac{x^2 - 6x}{x + 3} \)[/tex]