Section 6.4Solving Polynomial Equations

Obj: to solve polynomial equations

Solving by Graphing (only real solutions)

• Graph the related function and find its __________ or __________.

Graph and Solve: x3 + 3x2 – x – 3 = 0

Solutions: _______________

Recall:

Factoring a “Difference of Squares”

a2 – b2 = (a + b)(a – b)

Solving by Factoring a Sum or Difference of Cubes also has an

algorithym:

Sums of Cubes: + = ( a + b)(- ab + ) *signsDifferences of Cubes: - = ( a - b)(a2 + ab - ) *signs

Factor:Ex 1 - 8 =

Ex 2 + 125 =

Ex 3 -1 =

Solve.

• Ex 1 8 + 125 = 0

Solve.

• Ex 2 27 - 1= 0

Factor by Using a Quadratic Form.

Has the form of a quadratic, so factor it as one-----

• x4 + 7x2 + 6 x4 – 6x2 - 27

Solve.

• Ex 3 + 11 +18 = 0

Solve.

• Ex 4 -4x2 - 45 = 0

Solve by grouping.

• Ex 5 -- 9x + 9 = 0

Assign: Pg. 324 # 1-3, 12-14,15-31odd, 54