April 23: Solving Cubic Polynomials w/ Synthetic Division & Factoring

Post date: Apr 23, 2013 8:58:35 PM

Notes:

p(x)=ax^3+bx^2+cx+d------>p(x)=a(x-p)(x-q)(x-r)

Standard Form------>Factored Form

f(x)=x^3+x^2-10x+8

Step 1: Identify all possible x-intercepts (factors of constant)

Step 2: Use synthetic division to find first zero (factor that lets there be no remainder)

1I 1 1 -10 8

1 2 -8 (x-1)

1 2 -8 0 (x^2+2x-8)

Step 3: Re-write equation with the binomial you found and the trinomial you found

f(x)=(x-1)(x^2+2x-8)

Step 4: Factor quadratic term

f(x)=(x-1)(x+4)(x-2)

Step 5: Write x-intercepts

(1,0); (-4,0); (2,0)

Here is a video for more help:

Finding Roots to a Cubic Polynomial

Homework:

Sec 9.4 in packet: (13-20)

QUIZ ON SKILLS 36, 40 & 43 ON THURSDAY