Math Problem Statement

The functions f and g are defined as follows: f(x) = x^2 - 4x - 1 and g(x) = (9x - 5) / (x - 3). Find f(x + 7) and g(x / 2).

Solution

The image provides the functions f(x)=x24x1f(x) = x^2 - 4x - 1 and g(x)=9x5x3g(x) = \frac{9x - 5}{x - 3}, and you're asked to find f(x+7)f(x + 7) and g(x2)g\left(\frac{x}{2}\right).

1. Find f(x+7)f(x + 7)

To find f(x+7)f(x + 7), we substitute x+7x + 7 into the function f(x)f(x): f(x+7)=(x+7)24(x+7)1f(x + 7) = (x + 7)^2 - 4(x + 7) - 1

Now, simplify step-by-step:

(x+7)2=x2+14x+49(x + 7)^2 = x^2 + 14x + 49 4(x+7)=4x28-4(x + 7) = -4x - 28

Now substitute these into the function: f(x+7)=x2+14x+494x281f(x + 7) = x^2 + 14x + 49 - 4x - 28 - 1

Combine like terms: f(x+7)=x2+10x+20f(x + 7) = x^2 + 10x + 20

2. Find g(x2)g\left(\frac{x}{2}\right)

For g(x2)g\left(\frac{x}{2}\right), substitute x2\frac{x}{2} into the function g(x)g(x):

g(x2)=9(x2)5x23g\left(\frac{x}{2}\right) = \frac{9\left(\frac{x}{2}\right) - 5}{\frac{x}{2} - 3}

Simplify the numerator: 9(x2)=9x29\left(\frac{x}{2}\right) = \frac{9x}{2} 9x25=9x102\frac{9x}{2} - 5 = \frac{9x - 10}{2}

Simplify the denominator: x23=x62\frac{x}{2} - 3 = \frac{x - 6}{2}

Now the expression becomes: g(x2)=9x102x62g\left(\frac{x}{2}\right) = \frac{\frac{9x - 10}{2}}{\frac{x - 6}{2}}

Since both the numerator and denominator are divided by 2, they cancel out: g(x2)=9x10x6g\left(\frac{x}{2}\right) = \frac{9x - 10}{x - 6}

Final Answers:

  • f(x+7)=x2+10x+20f(x + 7) = x^2 + 10x + 20
  • g(x2)=9x10x6g\left(\frac{x}{2}\right) = \frac{9x - 10}{x - 6}

Would you like any more details or explanations?

Here are 5 related questions for practice:

  1. What is f(x3)f(x - 3) for the given function f(x)f(x)?
  2. How would you solve f(g(x))f(g(x)) for the functions given?
  3. Can you find the inverse of the function g(x)g(x)?
  4. What happens if you solve f(2x)f(2x) instead of f(x+7)f(x + 7)?
  5. How would you graph both f(x)f(x) and g(x)g(x) on the same coordinate plane?

Tip: Always expand and simplify step-by-step when substituting expressions into functions to avoid mistakes.

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Math Problem Analysis

Mathematical Concepts

Function substitution
Quadratic functions
Rational functions

Formulas

f(x) = x^2 - 4x - 1
g(x) = (9x - 5) / (x - 3)

Theorems

Function composition
Simplification of algebraic expressions

Suitable Grade Level

Grades 9-11