Math Problem Statement

How many roots do the functions have in common? [f(x)=x^2-4x-5] A coordinate plane. The x- and y-axes both scale by one. The graph is the function y equals g of x which is a parabola that opens up. The function has a y-intercept at zero, nine, an x-intercept at two, zero, a minimum around three point five, negative two, and another x-intercept at five, zero. [\small{1}] [\small{2}] [\small{3}] [\small{4}] [\small{5}] [\small{6}] [\small{7}] [\small{\llap{-}2}] [\small{\llap{-}3}] [\small{\llap{-}4}] [\small{\llap{-}5}] [\small{\llap{-}6}] [\small{\llap{-}7}] [\small{1}] [\small{2}] [\small{3}] [\small{4}] [\small{5}] [\small{6}] [\small{7}] [\small{\llap{-}2}] [\small{\llap{-}3}] [\small{\llap{-}4}] [\small{\llap{-}5}] [\small{\llap{-}6}] [\small{\llap{-}7}] [y] [x] [y=g(x)] Choose 1 answer: Choose 1 answer: (Choice A)
[f] and [g] share the same root(s). A [f] and [g] share the same root(s). (Choice B)
[f] and [g] share one root in common but each have another root that is not shared. B [f] and [g] share one root in common but each have another root that is not shared. (Choice C)
[f] and [g] share no roots in common. C [f] and [g] share no roots in common.

Solution

Let's break down the problem and analyze the given information step by step.

Given:

  • The function f(x)=x24x5f(x) = x^2 - 4x - 5 is a quadratic function.
  • We have a graph of another function g(x)g(x), which is a parabola that opens upwards, with the following characteristics:
    • The y-intercept is at (0,9)(0, 9), meaning g(0)=9g(0) = 9.
    • The x-intercepts are at x=2x = 2 and x=5x = 5, meaning g(2)=0g(2) = 0 and g(5)=0g(5) = 0.
    • The minimum is at approximately (3.5,2)(3.5, -2), suggesting the vertex of the parabola is near x=3.5x = 3.5 and g(x)g(x) reaches its lowest value there.

Step 1: Find the roots of f(x)f(x)

We start by factoring f(x)=x24x5f(x) = x^2 - 4x - 5:

f(x)=(x5)(x+1)f(x) = (x - 5)(x + 1)

So, the roots of f(x)f(x) are: x=5andx=1x = 5 \quad \text{and} \quad x = -1

Step 2: Analyze the roots of g(x)g(x)

From the graph description of g(x)g(x), we know the x-intercepts are at x=2x = 2 and x=5x = 5. This means the roots of g(x)g(x) are: x=2andx=5x = 2 \quad \text{and} \quad x = 5

Step 3: Compare the roots of f(x)f(x) and g(x)g(x)

  • f(x)f(x) has roots at x=5x = 5 and x=1x = -1.
  • g(x)g(x) has roots at x=2x = 2 and x=5x = 5.

The only root that f(x)f(x) and g(x)g(x) have in common is x=5x = 5.

Conclusion:

The functions f(x)f(x) and g(x)g(x) share one root in common, and each has another root that is not shared.

Thus, the correct answer is: (Choice B) ff and gg share one root in common but each have another root that is not shared.


Would you like a further explanation or help with another question? Here's a list of related topics to explore:

  1. How to factor quadratic equations.
  2. Understanding the vertex form of a parabola.
  3. Solving for the roots of quadratic functions.
  4. The connection between the graph of a quadratic and its factors.
  5. How to interpret and sketch quadratic graphs.

Tip: When factoring quadratics, always check if the coefficients are easily factorable, and if not, try the quadratic formula!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Roots of Functions
Graphing Quadratics

Formulas

Factoring quadratic equations
Quadratic formula (if needed)

Theorems

Zero Product Property
The Fundamental Theorem of Algebra

Suitable Grade Level

Grades 8-10