Math Problem Statement

If f(x) = x² - 2x, find f(k - 3).

Solution

The problem asks to evaluate f(k3)f(k - 3) given that f(x)=x22xf(x) = x^2 - 2x.

Solution:

We start by substituting k3k - 3 into the function f(x)f(x).

f(k3)=(k3)22(k3)f(k - 3) = (k - 3)^2 - 2(k - 3)

Step 1: Expand (k3)2(k - 3)^2:

(k3)2=k26k+9(k - 3)^2 = k^2 - 6k + 9

Step 2: Expand 2(k3)-2(k - 3):

2(k3)=2k+6-2(k - 3) = -2k + 6

Step 3: Combine terms:

f(k3)=k26k+92k+6f(k - 3) = k^2 - 6k + 9 - 2k + 6

f(k3)=k28k+15f(k - 3) = k^2 - 8k + 15

So, the final answer is:

f(k3)=k28k+15f(k - 3) = k^2 - 8k + 15

Would you like further explanation or a deeper breakdown?


Here are 5 related questions to extend your understanding:

  1. What is the general formula for evaluating f(a+b)f(a + b) for any function f(x)f(x)?
  2. How do you solve f(x)=0f(x) = 0 for this function?
  3. If f(x)=x22xf(x) = x^2 - 2x, what is the vertex of the parabola?
  4. How do you determine whether this function is increasing or decreasing for different values of xx?
  5. How would the answer change if the function was f(x)=x2+2xf(x) = x^2 + 2x instead?

Tip: When substituting a term into a function, always expand carefully and combine like terms to avoid mistakes!

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Math Problem Analysis

Mathematical Concepts

Function evaluation
Quadratic expressions
Algebraic substitution

Formulas

f(x) = x² - 2x
(a - b)² = a² - 2ab + b²

Theorems

Expansion of binomials
Combining like terms in algebra

Suitable Grade Level

Grades 9-10