Math Problem Statement

Evaluate the function f(x) = x^2 + 3x + 7 at the given values of the independent variable: a. f(-3), b. f(x+1), c. f(-x).

Solution

The problem asks you to evaluate the function f(x)=x2+3x+7f(x) = x^2 + 3x + 7 for three different values: f(3)f(-3), f(x+1)f(x+1), and f(x)f(-x). Let's go through each one step by step:

a. f(3)f(-3)

Substitute x=3x = -3 into the function:

f(3)=(3)2+3(3)+7=99+7=7f(-3) = (-3)^2 + 3(-3) + 7 = 9 - 9 + 7 = 7

So, f(3)=7f(-3) = 7.

b. f(x+1)f(x+1)

Substitute x+1x+1 into the function:

f(x+1)=(x+1)2+3(x+1)+7f(x+1) = (x+1)^2 + 3(x+1) + 7

Expanding the squares and simplifying:

(x+1)2=x2+2x+1(x+1)^2 = x^2 + 2x + 1 3(x+1)=3x+33(x+1) = 3x + 3

Now substitute into the function:

f(x+1)=(x2+2x+1)+(3x+3)+7=x2+5x+11f(x+1) = (x^2 + 2x + 1) + (3x + 3) + 7 = x^2 + 5x + 11

So, f(x+1)=x2+5x+11f(x+1) = x^2 + 5x + 11.

c. f(x)f(-x)

Substitute x-x into the function:

f(x)=(x)2+3(x)+7f(-x) = (-x)^2 + 3(-x) + 7

Simplify:

(x)2=x2(-x)^2 = x^2 3(x)=3x3(-x) = -3x

Now substitute into the function:

f(x)=x23x+7f(-x) = x^2 - 3x + 7

So, f(x)=x23x+7f(-x) = x^2 - 3x + 7.

Final answers:

  • f(3)=7f(-3) = 7
  • f(x+1)=x2+5x+11f(x+1) = x^2 + 5x + 11
  • f(x)=x23x+7f(-x) = x^2 - 3x + 7

Would you like further details on any of these steps?


Here are 5 follow-up questions to deepen your understanding:

  1. How would you evaluate f(x)f(x) for another arbitrary value, such as f(2)f(2)?
  2. What happens to the function f(x)f(x) if you substitute x=0x = 0?
  3. How would the result change for f(x1)f(x-1)?
  4. Can you derive the vertex form of the quadratic function f(x)=x2+3x+7f(x) = x^2 + 3x + 7?
  5. How would you find the roots of f(x)=0f(x) = 0?

Tip: Always simplify expressions step by step to avoid mistakes in expanding or factoring terms.

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Quadratic Functions
Substitution

Formulas

f(x) = x^2 + 3x + 7
Substitution of values into the function

Theorems

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Suitable Grade Level

Grades 8-10