Use the given graph of the polynomial function to complete the following.

a. Estimate the​ x-intercept(s).
b. State whether the leading coefficient is positive or negative.
c. Determine whether the polynomial function is cubic or quartic.
-5
-3
-1
1
3
5
-5
-3
-1
1
3
5
x
y

The​ x-intercepts are xequals
  
enter your response here.

1 answer

To answer your questions regarding the polynomial function based on the provided graph, let's go through each part step by step.

a. Estimate the x-intercept(s).

The x-intercepts of a polynomial function are the points where the graph intersects the x-axis. You would look at the graph and identify the x-values for which y = 0.

If we assume that you see crossings at specific points, you might estimate the x-intercepts to be:

  • \( x_1 = a \)
  • \( x_2 = b \) (if there are two intercepts)

For example, if the graph crosses at \( x = -3 \) and \( x = 1 \), you would write:

The x-intercepts are \( x = -3 \) and \( x = 1 \).

b. State whether the leading coefficient is positive or negative.

To determine if the leading coefficient is positive or negative, look at the end behavior of the graph:

  • If the graph rises to the right as you move along the x-axis (from left to right), then the leading coefficient is positive.
  • If the graph falls to the right, then the leading coefficient is negative.

If the graph rises to the right, you would state:

The leading coefficient is positive.

If it falls, you would state:

The leading coefficient is negative.

c. Determine whether the polynomial function is cubic or quartic.

  • A cubic polynomial has a degree of 3 and typically has 1 or 3 real roots (x-intercepts) and an "S" shaped graph.
  • A quartic polynomial has a degree of 4 and usually has up to 4 real roots, and its graph can have a "W" shaped appearance.

You would look at the number of turns in the graph:

  • If there are up to 3 turning points, it's likely cubic.
  • If there are up to 4 turning points, it's probably quartic.

For example, if you see the graph has 3 turning points, you would state:

The polynomial function is cubic.

If there are 4 turning points, you would state:

The polynomial function is quartic.

Summary Example

Let's say you observed the following from the graph:

  • x-intercepts at -3 and 1.
  • The graph rises to the right, indicating a positive leading coefficient.
  • The graph appears to have three turning points.

You would complete your answers as follows:

  • The x-intercepts are \( x = -3 \) and \( x = 1 \).
  • The leading coefficient is positive.
  • The polynomial function is cubic.

Feel free to adjust the estimates based on what you see in your specific graph!