Math Problem Statement

Find f(x + 7) and g(x/2) where f(x) = x^2 - 4x - 1 and g(x) = (9x - 5)/(x - 3). Simplify the answers as much as possible.

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.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Function Substitution
Rational Functions
Simplification

Formulas

f(x) = x^2 - 4x - 1
g(x) = (9x - 5) / (x - 3)
Quadratic expansion: (a + b)^2 = a^2 + 2ab + b^2

Theorems

Simplification of Rational Functions
Polynomial Expansion

Suitable Grade Level

Grades 10-12