1. 4.3 Solve x2 + bx +c = 0 by Factoring

2. Vocabulary: Monomial: one term
(ex) x (ex) 4 (ex) 4x (ex) 4xy2 (ex) 3x3y2z
Binomial: two terms
(ex) x (ex) 3x – 2 (ex) 4x2 + 5
Trinomial: three terms
(ex) x2 + 2x (ex) 4x4 + 3x2 – 16x

3. Factor the Expression form x2 + bx + c
Factored form : (x + #) (x + #)
Second sign of the trinomial identifies same (+) or different (-) signs have to be used in the binomials:
First sign of the trinomial goes to both binomials if same is determined.
First sign of the trinomial goes to the binomial with the largest number if different is determined.
To identify the numbers in the binomials: the numbers must multiply to make “c” and add or subtract to create “b”.

4. Examples:
(ex) x2 – 9x + 20
(ex) x2 + 3x - 12

5. Page 252 (1-3)

6. Special Pattern Difference of Squares: a2 - b2 = (a +b) (a – b)
(ex) x2 – 4 = (x + 2) (x – 2)
Perfect Trinomial:
a2 + 2ab + b2 = (a+b)2
(ex) x2 + 6x + 9 = (x + 3)2
a2 - 2ab + b2 = (a - b)2
(ex) x2 – 4x + 4 = (x – 2)2

7. Factor with Special Patterns
(ex) x2 – (ex) 4x2 - 16
(ex) x (ex) 100x2 + 64

8. Factor with Special Pattern
(ex) d2 + 12d + 36
(ex) z2 – 26z + 169

9. Practice Problems: Page 253 (4-7)

10. Solve a Quadratic Equation
1) Make sure the equation is in Standard Form
2) Factor the equation
3) Set the factored form equal to zero and
solve for the variable.
Solving an equation could be asked by the question: Find the zero’s of the function.

11. Practice Problems: (ex) x2 – 5x + 6 = 0 1) Standard Form
(x – 3) (x – 2) ) Factor
x – 3 = 0 x – 2 = ) Solve for x
x = x = 2
(ex) 8x – 16 = x Rewrite in Standard
Form
Factor and Solve