Unit #7.Lesson #5.Factoring Trinomials

Lesson 4 Day 2: Factoring trinomials when a > 1

Warm UP

x2  5x  24 ? 1. Which of the following products is equivalent to the trinomial

(1)  x 12 x  2 (3)  x  8 x  3

(2)  x 12 x  2 (4)  x  8 x  3

2. Written in factored form, the trinomial 2x2 15x  28 can be expressed equivalently as

(1) 2x  7 x  4 (3) 2x  2 x 14

(2) 2x  4 x  7 (4) 2x 14 x  2

3. (Easier) Write each of the following trinomials in equivalent factored form. Keep at it!!! Use extra scrap paper for extra guesses.

(a) x2 10x (b) x2 12x  35 (c) x2 12x  36 16

(e) x2 11x  (f) x2 12x  20 (d) x2  5x  6 28 4. (Medium) Write each of the following trinomials in equivalent factored form. Keep at it!!! SPLIT THE LINEAR TERM

2 (a) 2x 13x  21 (b) 5x2  21x  4 (c) 3x2 16x 12

2 (d) 7x 11x  6 (e) 2x2  x 10 (f) 11x2 10x 1

5. (Hardest) Write each of the following trinomials in equivalent factored form. Keep at it!!! These might require quite a few tries. You will get better at them as you practice. Use extra scrap paper for extra guesses.

2 (a) 4x  27x (b) 6x2  5x  4 (c) 12x2  31x  20 18

APPLICATIONS

6. A rectangle has dimensions as shown below in terms of an unknown variable, x.

(a) Find a binomial expression for the width of the rectangle in terms of x. Justify your answer based on the expressions for Length  x  4 the rectangle’s length and area.

Width = ? (b) If the width of the rectangle is 21 inches, what is the length and the area? Use appropriate units and explain how you found your answer.