1. P.4B Factoring Polynomials
Ex Factor 2x2 + x – 15
Write 2 ( ) with 2x in each
we know there’s an extra 2, we’ll get rid of it later
(2x )(2x )
As yourself, what multiplies to get 30 (multiply first and last numbers) and SUBTRACTS to 1
(2x 5)(2x 6)
Now place + and – in appropriate spots
(2x – 5)(2x + 6)
Remember the extra 2 from step one? Find it, pull it out and get rid of it.
(2x – 5)(x + 3)

2. Ex. 9 Factor by grouping. x3 – 2x2 – 3x + 6
Because of the “-” in the middle, when you pull a negative out of + 6, it becomes a – 6
(x3 – 2x2) – (3x – 6)
Factor what’s common to both groups out front of each group
x2(x – 2) – 3(x – 2)
Your ( ) should be the same. Pull that out front and rewrite what’s left.
(x – 2)(x2 – 3)

3. Ex. 10 Use factoring by grouping to factor 2x2 + 5x – 3
Rewrite middle term
Keep in mind we’re trying to group values together like ex 9
2x2 + 6x – x – 3
Group terms
(2x2 + 6x) – (x + 3)
Factor groups
2x(x + 3) – 1(x + 3)
Pull out what’s common
(x + 3)(2x – 1)
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