STANDARD A.APR.B.3
AI
Identify zeros of polynomial functions when suitable factorizations are available.Β Tasks will focus on identifying the zeros of quadratic and cubic polynomial functions.Β For tasks that involve finding the zeros of cubic polynomial functions, the linear and quadratic factors of the cubic polynomial function will be given (e.g., find the zeros of P(x)=(x-2)(x2-9)).
AII
Identify zeros of polynomial functions when suitable factorizations are available.
Zero of a Polynomial
A number that, when substituted for x, makes the entire polynomial equal to zero.
π Example: If f(x)=x2β4f(x) = x^2 - 4f(x)=x2β4, then x=2x = 2x=2 and x=β2x = -2x=β2 are zeros because f(2)=0f(2) = 0f(2)=0 and f(β2)=0f(-2) = 0f(β2)=0.
Root
Another word for a zero of a polynomial. They mean the same thing!
π Think of it as: roots = zeros = solutions.
Solution
A value of x that makes the equation f(x)=0f(x) = 0f(x)=0 true.
π When you solve a polynomial equation, you're finding its solutions (which are the same as zeros and roots).
x-intercept
The point(s) where the graph of the polynomial crosses or touches the x-axis.
π These points have the form (x,0)(x, 0)(x,0), and the x-values are the zeros.
π Example: If the graph crosses the x-axis at (3,0)(3, 0)(3,0), then 3 is a zero of the polynomial.
Worksheet: A.APR.B.3: Zeros of PolynomialsΒ
Khan Academy Practice: Link
How to find zeros on TI-84 calculator:
Worksheet: A.APR.B.3: Graphing Polynomial FunctionsΒ
Khan Academy Practice: Link