Math Problem Statement

For the given functions f(x) = x - 9 and g(x) = 6x^2, complete parts (a) to (h). (e) Find (f + g)(3), (f) Find (f - g)(2), (g) Find (f ⋅ g)(4), (h) Find (f/g)(1).

Solution

Let's solve the given problems step-by-step. The functions provided are:

f(x)=x9f(x) = x - 9 g(x)=6x2g(x) = 6x^2

(e) Find (f+g)(3)(f + g)(3):

(f+g)(x)=f(x)+g(x)=(x9)+6x2(f + g)(x) = f(x) + g(x) = (x - 9) + 6x^2

Plugging in x=3x = 3: (f+g)(3)=(39)+6×32(f + g)(3) = (3 - 9) + 6 \times 3^2 (f+g)(3)=6+6×9(f + g)(3) = -6 + 6 \times 9 (f+g)(3)=6+54=48(f + g)(3) = -6 + 54 = 48

Answer for (e): (f+g)(3)=48(f + g)(3) = 48

(f) Find (fg)(2)(f - g)(2):

(fg)(x)=f(x)g(x)=(x9)6x2(f - g)(x) = f(x) - g(x) = (x - 9) - 6x^2

Plugging in x=2x = 2: (fg)(2)=(29)6×22(f - g)(2) = (2 - 9) - 6 \times 2^2 (fg)(2)=76×4(f - g)(2) = -7 - 6 \times 4 (fg)(2)=724=31(f - g)(2) = -7 - 24 = -31

Answer for (f): (fg)(2)=31(f - g)(2) = -31

(g) Find (fg)(4)(f \cdot g)(4):

(fg)(x)=f(x)g(x)=(x9)6x2(f \cdot g)(x) = f(x) \cdot g(x) = (x - 9) \cdot 6x^2

Plugging in x=4x = 4: (fg)(4)=(49)6×42(f \cdot g)(4) = (4 - 9) \cdot 6 \times 4^2 (fg)(4)=56×16(f \cdot g)(4) = -5 \cdot 6 \times 16 (fg)(4)=596=480(f \cdot g)(4) = -5 \cdot 96 = -480

Answer for (g): (fg)(4)=480(f \cdot g)(4) = -480

(h) Find (fg)(1)\left(\frac{f}{g}\right)(1):

(fg)(x)=f(x)g(x)=x96x2\left(\frac{f}{g}\right)(x) = \frac{f(x)}{g(x)} = \frac{x - 9}{6x^2}

Plugging in x=1x = 1: (fg)(1)=196×12\left(\frac{f}{g}\right)(1) = \frac{1 - 9}{6 \times 1^2} (fg)(1)=86\left(\frac{f}{g}\right)(1) = \frac{-8}{6} (fg)(1)=43\left(\frac{f}{g}\right)(1) = -\frac{4}{3}

Answer for (h): (fg)(1)=43\left(\frac{f}{g}\right)(1) = -\frac{4}{3}


Do you need any more details or have any questions? Here are some related questions:

  1. What is the domain of the function (fg)(x)\left(\frac{f}{g}\right)(x)?
  2. How would you find (f+g)(x)(f + g)(x) in its simplified form?
  3. What is the value of (fg)(x)(f - g)(x) when x=0x = 0?
  4. Can you find the zeros of the function g(x)g(x)?
  5. What would be the derivative of f(x)f(x) and g(x)g(x)?

Tip: Always verify the domain of your function, especially when dealing with divisions to avoid undefined values.

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Math Problem Analysis

Mathematical Concepts

Function operations
Substitution
Algebra

Formulas

(f + g)(x) = f(x) + g(x)
(f - g)(x) = f(x) - g(x)
(f ⋅ g)(x) = f(x) ⋅ g(x)
(f / g)(x) = f(x) / g(x)

Theorems

Basic function operations and evaluation

Suitable Grade Level

Grades 9-11