Given f(x) = (x − 1)(x + 2)(x − 3), what are the zeros and end behavior of the function?

−1, 2, −3; continues downward to the left and upward to the right
−1, 2, −3; continues upward to the left and downward to the right
1, −2, 3; continues downward to the left and upward to the right
1, −2, 3; continues upward to the left and downward to the right

1 answer

To find the zeros of the function \( f(x) = (x - 1)(x + 2)(x - 3) \), we set the function equal to zero and solve for \( x \):

  1. \( x - 1 = 0 \) ⇒ \( x = 1 \)
  2. \( x + 2 = 0 \) ⇒ \( x = -2 \)
  3. \( x - 3 = 0 \) ⇒ \( x = 3 \)

Thus, the zeros of the function \( f(x) \) are \( x = 1, -2, 3 \).

Next, we analyze the end behavior of the function. The polynomial is of degree 3 (since the highest power of \( x \) in the expanded version is \( x^3 \)). The leading coefficient is positive, as it comes from the expansion of the function.

For a polynomial of odd degree with a positive leading coefficient:

  • As \( x \to -\infty \), \( f(x) \to -\infty \) (the function goes downward to the left).
  • As \( x \to +\infty \), \( f(x) \to +\infty \) (the function goes upward to the right).

Combining this information, we have:

  • Zeros: \( 1, -2, 3 \)
  • End behavior: continues downward to the left and upward to the right.

The correct choice that matches this analysis is:

1, -2, 3; continues downward to the left and upward to the right.