Section 5.2

1. Section 5.2 Factoring Trinomials Of the Type x2 + bx +c Phong Chau

2. x2 + 5x + 2x + 10 ( x + 2 )( x + 5) = = x2 + 7x + 10 • The product of 2 binomials is a trinomial. • The constant term in the trinomial is the product of the constant terms in the binomials. • The coefficient of x in the trinomial is the sum of the constant terms in the binomials

3. x2 - 7x + 3x - 21 ( x + 3 )( x - 7) = = x2 - 4x- 21 • The constant term in the trinomial is negative constant terms in the binomials are opposite in sign: • One must be positive + • The other is negative -

4. Factoring trinomials of the form x2 + bx + c: • The factored form must be product of 2 binomials ( x )( x ) • To figure out the constants, look for 2 integers whose product is c and whose sum is b: • List all factor pairs of c. • Choose the factor pair whose sum is b

5. Examples 1) x2 + 7x + 10 2) x2 + 4x - 12 3) x2 - 6x - 16 4) 2a3 - 20a2 + 50a

6. Examples • http://www.ccsn.nevada.edu/math/factoring.htm • http://karensworld.com/algebra/algebra2-1.html

7. Group exercise 1) x2 - 8x + 16 2) m2n + 4mn - 12n 3)6x2y2 + 24xy2 + 18y2