Zeros of Polynomial
Functions
Give the prime factors of the following:
1. 28
2. 45
3. 54
Review:
1: One common factor. a x + a y = a (x + y)
2x + 2y = 2 (x + y)
2: Several grouped common
factor. a x + a y + b x + b y = a(x + y)
+ b(x + y) = (a + b ) (x + y)
3. Difference of two squares
x 2 - y 2 = (x + y)(x - y)
x 2 - 49 = (x + 7)(x - 7)
4: Difference of two squares
(x + y) 2 - z 2 = (x + y + z)(x + y - z)
(2x + 3) 2 - 49 = (2x + 3 + 7)(2x + 3 - 7)
5: Sum of two cubes.
x 3 + y 3 = (x + y)(x 2 - x y + y 2)
x3 + 27 = (x + 3)(x2- 3x + 9)
6: Difference of two cubes.
x 3 - y 3 = (x - y)(x 2 + x y + y 2)
x3 - 125 = (x - 5)(x2 + 5x + 25)
7: Difference of fourth Powers.
x 4 - y 4 = (x 2 - y 2)(x 2 + y 2) =
(x + y)(x - y)(x 2 + y 2)
x 4 - 16 = (x 2 - 4)(x 2 + 4)
(x - 2)(x + 2)(x 2 + 4)
8: Perfect square
x 2 + 2xy + y 2 = (x + y) 2
x 2 + 8x + 16 = (x + 4)
9: Perfect square
x 2 - 2xy + y 2 = (x - y) 2
x 2 - 10x + 25 = (x - 5)
11: Perfect cube
x 3 - 3x 2y + 3xy 2 - y 3 = (x - y) 3
10: Perfect cube
x 3 + 3x 2y + 3xy 2 + y 3 = (x + y) 3
x 3 + 21x 2 + 147x + 343 = (x + 7) 3
x 3 - 6x 2 + 12x - 8 = (x - 2) 3
Factor the polynomials.
1: (x + 1) 2 - 4
2: x 2 + 5x + 6
3: x 3 - 1
4: x 3 - x 2 - 25x + 25
Find all zeros.
1) f (x) = (2x − 1)(x − 5)
2) f (x) = (x − 3)2(3x + 1)(x + 1)
3) f (x) = (2x + 1)(x + 1)3(x − 1)
4) f (x) = x(2x − 1)(x − 1)(x + 1)
5) f (x) = x3 − 3x2 − 4x + 12
6) f (x) = x4 + 2x3 − 13x2 − 14x + 24
7) f (x) = x3 − 4x2 − 5x
8) f (x) = x3 − 2x2 + x
9) f(x) = x3 - 2x2 + 2x - 4
10) f(x) = x4 - 16x3 + 94x2 - 240x + 225

Zeros of polynomial functions

  • 1.
  • 2.
    Give the primefactors of the following: 1. 28 2. 45 3. 54
  • 3.
    Review: 1: One commonfactor. a x + a y = a (x + y) 2x + 2y = 2 (x + y) 2: Several grouped common factor. a x + a y + b x + b y = a(x + y) + b(x + y) = (a + b ) (x + y)
  • 4.
    3. Difference oftwo squares x 2 - y 2 = (x + y)(x - y) x 2 - 49 = (x + 7)(x - 7) 4: Difference of two squares (x + y) 2 - z 2 = (x + y + z)(x + y - z) (2x + 3) 2 - 49 = (2x + 3 + 7)(2x + 3 - 7)
  • 5.
    5: Sum oftwo cubes. x 3 + y 3 = (x + y)(x 2 - x y + y 2) x3 + 27 = (x + 3)(x2- 3x + 9) 6: Difference of two cubes. x 3 - y 3 = (x - y)(x 2 + x y + y 2) x3 - 125 = (x - 5)(x2 + 5x + 25)
  • 6.
    7: Difference offourth Powers. x 4 - y 4 = (x 2 - y 2)(x 2 + y 2) = (x + y)(x - y)(x 2 + y 2) x 4 - 16 = (x 2 - 4)(x 2 + 4) (x - 2)(x + 2)(x 2 + 4)
  • 7.
    8: Perfect square x2 + 2xy + y 2 = (x + y) 2 x 2 + 8x + 16 = (x + 4) 9: Perfect square x 2 - 2xy + y 2 = (x - y) 2 x 2 - 10x + 25 = (x - 5)
  • 8.
    11: Perfect cube x3 - 3x 2y + 3xy 2 - y 3 = (x - y) 3 10: Perfect cube x 3 + 3x 2y + 3xy 2 + y 3 = (x + y) 3 x 3 + 21x 2 + 147x + 343 = (x + 7) 3 x 3 - 6x 2 + 12x - 8 = (x - 2) 3
  • 9.
    Factor the polynomials. 1:(x + 1) 2 - 4 2: x 2 + 5x + 6 3: x 3 - 1 4: x 3 - x 2 - 25x + 25
  • 10.
    Find all zeros. 1)f (x) = (2x − 1)(x − 5) 2) f (x) = (x − 3)2(3x + 1)(x + 1) 3) f (x) = (2x + 1)(x + 1)3(x − 1) 4) f (x) = x(2x − 1)(x − 1)(x + 1)
  • 11.
    5) f (x)= x3 − 3x2 − 4x + 12 6) f (x) = x4 + 2x3 − 13x2 − 14x + 24 7) f (x) = x3 − 4x2 − 5x 8) f (x) = x3 − 2x2 + x 9) f(x) = x3 - 2x2 + 2x - 4 10) f(x) = x4 - 16x3 + 94x2 - 240x + 225