Math  /  Algebra

QuestionFind f+g,fg,fgf+g, f-g, f g and fg\frac{f}{g}. Determine the domain for each function. f(x)=6x5,g(x)=x+6f(x)=6 x-5, g(x)=x+6 (f+g)(x)=(f+g)(x)= \square (Simplify your answer.)

Studdy Solution

STEP 1

1. We are given two functions f(x)=6x5 f(x) = 6x - 5 and g(x)=x+6 g(x) = x + 6 .
2. We need to find the expressions for f+g f+g , fg f-g , fg fg , and fg \frac{f}{g} .
3. We also need to determine the domain for each resulting function.

STEP 2

1. Calculate (f+g)(x) (f+g)(x) and determine its domain.
2. Calculate (fg)(x) (f-g)(x) and determine its domain.
3. Calculate (fg)(x) (fg)(x) and determine its domain.
4. Calculate (fg)(x) \left(\frac{f}{g}\right)(x) and determine its domain.

STEP 3

Calculate (f+g)(x) (f+g)(x) :
(f+g)(x)=f(x)+g(x)=(6x5)+(x+6) (f+g)(x) = f(x) + g(x) = (6x - 5) + (x + 6)
Simplify the expression:
(f+g)(x)=6x5+x+6=7x+1 (f+g)(x) = 6x - 5 + x + 6 = 7x + 1
The domain of f+g f+g is all real numbers, R\mathbb{R}, because both f(x) f(x) and g(x) g(x) are linear functions with no restrictions.

STEP 4

Calculate (fg)(x) (f-g)(x) :
(fg)(x)=f(x)g(x)=(6x5)(x+6) (f-g)(x) = f(x) - g(x) = (6x - 5) - (x + 6)
Simplify the expression:
(fg)(x)=6x5x6=5x11 (f-g)(x) = 6x - 5 - x - 6 = 5x - 11
The domain of fg f-g is all real numbers, R\mathbb{R}, because both f(x) f(x) and g(x) g(x) are linear functions with no restrictions.

STEP 5

Calculate (fg)(x) (fg)(x) :
(fg)(x)=f(x)g(x)=(6x5)(x+6) (fg)(x) = f(x) \cdot g(x) = (6x - 5)(x + 6)
Expand the expression:
(fg)(x)=6x2+36x5x30=6x2+31x30 (fg)(x) = 6x^2 + 36x - 5x - 30 = 6x^2 + 31x - 30
The domain of fg fg is all real numbers, R\mathbb{R}, because polynomial functions are defined for all real numbers.

STEP 6

Calculate (fg)(x) \left(\frac{f}{g}\right)(x) :
(fg)(x)=f(x)g(x)=6x5x+6 \left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{6x - 5}{x + 6}
The domain of fg \frac{f}{g} is all real numbers except where the denominator is zero. Set the denominator equal to zero and solve for x x :
x+6=0 x + 6 = 0 x=6 x = -6
Thus, the domain of fg \frac{f}{g} is all real numbers except x=6 x = -6 , or R{6}\mathbb{R} \setminus \{-6\}.

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