Which graph represents the function of f(x) = the quantity of 4 x squared minus 16, all over 2 x minus 4?

graph of 2 x plus 4, with discontinuity at negative 2, 0
graph of 2 x plus 4, with discontinuity at 2, 8
graph of 2 x minus 4, with discontinuity at negative 2, negative 8
graph of 2 x minus 4, with discontinuity at 2, 0

1 answer

To analyze the function \( f(x) = \frac{4x^2 - 16}{2x - 4} \), we first simplify it.

Step 1: Factor the numerator. The numerator \( 4x^2 - 16 \) can be factored as follows: \[ 4x^2 - 16 = 4(x^2 - 4) = 4(x - 2)(x + 2) \]

Step 2: Factor the denominator. The denominator \( 2x - 4 \) can be factored out as: \[ 2x - 4 = 2(x - 2) \]

Step 3: Rewrite the function. Now we can rewrite the function: \[ f(x) = \frac{4(x - 2)(x + 2)}{2(x - 2)} \]

Step 4: Simplify. We can cancel out the \( (x - 2) \) term (keeping in mind that this introduces a restriction, as \( x \neq 2 \)): \[ f(x) = 2(x + 2), \quad x \neq 2 \]

So, the simplified function \( f(x) = 2(x + 2) \) is valid for all \( x \) except for \( x = 2 \), where there is a discontinuity.

Step 5: Identify characteristics. The simplified function is a linear function with a slope of 2 and a y-intercept of 4, except it is undefined at \( x = 2 \) (which is a removable discontinuity).

Conclusion: Choice based on the options:

  • The line \( f(x) = 2x + 4 \) has a slope of 2 and a y-intercept of 4.
  • The function is discontinuous at \( x = 2 \).

Given the options, the correct representation of the function is:

  • Graph of \( 2x + 4 \), with a discontinuity at \( 2, 0 \).