Math Problem Statement

Evaluate the functions f(x), g(x), h(x) and their limits as x approaches 3. Check for continuity at x = 3 for each function.

Solution

Let's go through the questions from the image one by one.

1. Evaluate each function:

a) f(3)f(3)

Given: f(x)=x29x3f(x) = \frac{x^2 - 9}{x - 3}

Factor the numerator: f(x)=(x3)(x+3)x3f(x) = \frac{(x - 3)(x + 3)}{x - 3} For x=3x = 3, the denominator becomes zero, so the function is undefined. Hence: f(3)=DNE (Does Not Exist)f(3) = \text{DNE (Does Not Exist)}

b) g(3)g(3)

Given: g(x)=x2+6xx23xg(x) = \frac{x^2 + 6x}{x^2 - 3x} Factor both the numerator and denominator: g(x)=x(x+6)x(x3)g(x) = \frac{x(x + 6)}{x(x - 3)} At x=3x = 3, the denominator is zero, so g(3)=DNEg(3) = \text{DNE}.

c) h(3)h(3)

Given: h(x)=x28x33x2+4x+3h(x) = \frac{x^2 - 8x - 33}{x^2 + 4x + 3} Substitute x=3x = 3: h(3)=328(3)3332+4(3)+3=924339+12+3=4824=2h(3) = \frac{3^2 - 8(3) - 33}{3^2 + 4(3) + 3} = \frac{9 - 24 - 33}{9 + 12 + 3} = \frac{-48}{24} = -2 So: h(3)=2h(3) = -2


2. Evaluate each limit:

a) limx3f(x)\lim_{x \to 3} f(x)

Since: f(x)=(x3)(x+3)x3f(x) = \frac{(x - 3)(x + 3)}{x - 3} Cancel the (x3)(x - 3) terms: limx3f(x)=limx3(x+3)=6\lim_{x \to 3} f(x) = \lim_{x \to 3} (x + 3) = 6

b) limx3g(x)\lim_{x \to 3} g(x)

For g(x)=x(x+6)x(x3)g(x) = \frac{x(x + 6)}{x(x - 3)}, simplify: g(x)=x+6x3g(x) = \frac{x + 6}{x - 3} As x3x \to 3, the denominator tends to zero, so: limx3g(x)=DNE (Undefined)\lim_{x \to 3} g(x) = \text{DNE (Undefined)}

c) limx3h(x)\lim_{x \to 3} h(x)

Since h(x)h(x) is defined at x=3x = 3, the limit can be evaluated as the function value: limx3h(x)=h(3)=2\lim_{x \to 3} h(x) = h(3) = -2


3. Continuity at x=3x = 3:

  • f(x)f(x) is not continuous at x=3x = 3 because f(3)f(3) does not exist.
  • g(x)g(x) is not continuous at x=3x = 3 because g(3)g(3) does not exist.
  • h(x)h(x) is continuous at x=3x = 3 because both h(3)h(3) exists and ( \lim_{x

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Math Problem Analysis

Mathematical Concepts

Limits
Continuity
Algebraic Simplification
Quadratic Functions

Formulas

f(x) = (x^2 - 9) / (x - 3)
g(x) = (x^2 + 6x) / (x^2 - 3x)
h(x) = (x^2 - 8x - 33) / (x^2 + 4x + 3)

Theorems

Limit Laws
Continuity Theorem
Factorization for Simplification

Suitable Grade Level

Grades 10-12