Questions: Factor the polynomial and use the factored form to find the zeros. (Enter your answers as a comma-separated list. Enter all answers using the appropriate multiplicities.)
P(x)=x^3-2 x^2-15 x
x=
Sketch the graph.
Transcript text: Factor the polynomial and use the factored form to find the zeros. (Enter your answers as a comma-separated list. Enter all answers using the appropriate multiplicities.)
\[
P(x)=x^{3}-2 x^{2}-15 x
\]
$x=$ $\square$
Sketch the graph.
Solution
Solution Steps
Step 1: Factor the Polynomial
The given polynomial is
\[
P(x) = x^3 - 2x^2 - 15x
\]
First, factor out the greatest common factor, which is \(x\):
\[
P(x) = x(x^2 - 2x - 15)
\]
Next, factor the quadratic expression \(x^2 - 2x - 15\). We need two numbers that multiply to \(-15\) and add to \(-2\). These numbers are \(-5\) and \(3\). Therefore, the quadratic can be factored as:
\[
x^2 - 2x - 15 = (x - 5)(x + 3)
\]
Thus, the factored form of the polynomial is:
\[
P(x) = x(x - 5)(x + 3)
\]
Step 2: Find the Zeros of the Polynomial
To find the zeros, set each factor equal to zero:
\(x = 0\)
\(x - 5 = 0 \Rightarrow x = 5\)
\(x + 3 = 0 \Rightarrow x = -3\)
The zeros of the polynomial are \(x = 0\), \(x = 5\), and \(x = -3\).