Table of contents
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
- 4. Polynomial Functions1h 54m
- 5. Rational Functions1h 23m
- 6. Exponential and Logarithmic Functions2h 28m
- 7. Measuring Angles40m
- 8. Trigonometric Functions on Right Triangles2h 5m
- 9. Unit Circle1h 19m
- 10. Graphing Trigonometric Functions1h 19m
- 11. Inverse Trigonometric Functions and Basic Trig Equations1h 41m
- 12. Trigonometric Identities 2h 34m
- 13. Non-Right Triangles1h 38m
- 14. Vectors2h 25m
- 15. Polar Equations2h 5m
- 16. Parametric Equations1h 6m
- 17. Graphing Complex Numbers1h 7m
- 18. Systems of Equations and Matrices3h 6m
- 19. Conic Sections2h 36m
- 20. Sequences, Series & Induction1h 15m
- 21. Combinatorics and Probability1h 45m
- 22. Limits & Continuity1h 49m
- 23. Intro to Derivatives & Area Under the Curve2h 9m
4. Polynomial Functions
Understanding Polynomial Functions
Struggling with Precalculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Find the zeros of the given polynomial function and give the multiplicity of each. State whether the graph crosses or touches the x-axis at each zero. f(x)=x2(x−1)3(2x+6)
A
Cross at x=0, Cross at x=1, Cross at x=3
B
Touch at x=0, Cross at x=−1, Cross at x=3
C
Cross at x=0, Touch at x=1, Touch at x=−3
D
Touch at x=0, Cross at x=1, Cross at x=−3

1
Identify the factors of the polynomial function f(x) = x^2(x-1)^3(2x+6). The factors are x^2, (x-1)^3, and (2x+6).
Set each factor equal to zero to find the zeros of the polynomial: x^2 = 0, (x-1)^3 = 0, and 2x+6 = 0.
Solve each equation for x: For x^2 = 0, x = 0. For (x-1)^3 = 0, x = 1. For 2x+6 = 0, x = -3.
Determine the multiplicity of each zero: x = 0 has multiplicity 2, x = 1 has multiplicity 3, and x = -3 has multiplicity 1.
Analyze the behavior of the graph at each zero: If the multiplicity is odd, the graph crosses the x-axis. If the multiplicity is even, the graph touches the x-axis. Therefore, the graph touches at x = 0, crosses at x = 1, and crosses at x = -3.
Watch next
Master Introduction to Polynomial Functions with a bite sized video explanation from Patrick
Start learning