1. **State the problem:** Find the roots of the cubic polynomial $$x^3 + 4x^2 - 17x - 60$$ and verify them.
2. **Formula and rules:** To find roots of a cubic polynomial, we can try factoring by grouping or use the Rational Root Theorem to test possible roots.
3. **Apply Rational Root Theorem:** Possible rational roots are factors of the constant term 60 divided by factors of the leading coefficient 1, i.e., $$\pm1, \pm2, \pm3, \pm4, \pm5, \pm6, \pm10, \pm12, \pm15, \pm20, \pm30, \pm60$$.
4. **Test roots:** Substitute $x = -6$:
$$(-6)^3 + 4(-6)^2 - 17(-6) - 60 = -216 + 144 + 102 - 60 = -30 \neq 0$$
Try $x = -2$:
$$(-2)^3 + 4(-2)^2 - 17(-2) - 60 = -8 + 16 + 34 - 60 = -18 \neq 0$$
Try $x = 5$:
$$5^3 + 4(5)^2 - 17(5) - 60 = 125 + 100 - 85 - 60 = 80 \neq 0$$
5. **Re-examine the problem:** The graph shows roots at $x = -6, -2, 5$. Let's verify carefully:
At $x = -6$:
$$(-6)^3 + 4(-6)^2 - 17(-6) - 60 = -216 + 144 + 102 - 60 = -30$$ (not zero, so check calculation)
Recalculate:
$$-216 + 144 = -72$$
$$-72 + 102 = 30$$
$$30 - 60 = -30$$
So $x = -6$ is not a root.
At $x = -2$:
$$-8 + 16 + 34 - 60 = -18$$ not zero.
At $x = 5$:
$$125 + 100 - 85 - 60 = 80$$ not zero.
6. **Try synthetic division with $x = 3$:**
Coefficients: 1, 4, -17, -60
Bring down 1:
Multiply 1*3=3, add to 4=7
Multiply 7*3=21, add to -17=4
Multiply 4*3=12, add to -60=-48
Remainder is -48, not zero.
7. **Try $x = -5$:**
Bring down 1:
Multiply 1*(-5)=-5, add to 4=-1
Multiply -1*(-5)=5, add to -17=-12
Multiply -12*(-5)=60, add to -60=0
Remainder zero, so $x = -5$ is a root.
8. **Divide polynomial by $(x + 5)$:**
$$\frac{x^3 + 4x^2 - 17x - 60}{x + 5} = x^2 - x - 12$$
9. **Factor quadratic:**
$$x^2 - x - 12 = (x - 4)(x + 3)$$
10. **Roots:**
$$x = -5, 4, -3$$
**Final answer:** The roots of the polynomial are $$\boxed{-5, 4, -3}$$.
Cubic Roots Ac43F5
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