1. HW: 6.2 Practice Worksheet

4. EXAMPLE 1 Add polynomials vertically and horizontally a. Add 2x 3 – 5x 2 + 3x – 9 and x 3 + 6x 2 + 11 in a vertical format. SOLUTION a. 2x 3 – 5x 2 + 3x – 9 + x 3 + 6x 2 + 11 3x 3 + x 2 + 3x + 2 (3y 3 – 2y 2 – 7y) + (–4y 2 + 2y – 5) = 3y 3 – 2y 2 – 4y 2 – 7y + 2y – 5 = 3y 3 – 6y 2 – 5y – 5 b. Add 3y 3 – 2y 2 – 7y and –4y 2 + 2y – 5 in a horizontal format. b.

5. EXAMPLE 2 Subtract polynomials vertically and horizontally a. Subtract 3x 3 + 2x 2 – x + 7 from 8x 3 – x 2 – 5x + 1 in a vertical format. SOLUTION a. Align like terms, then add the opposite of the subtracted polynomial. 8x 3 – x 2 – 5x + 1 – (3x 3 + 2x 2 – x + 7) 8x 3 – x 2 – 5x + 1 + – 3x 3 – 2x 2 + x – 7 5x 3 – 3x 2 – 4x – 6 b. Subtract 5z 2 – z + 3 from 4z 2 + 9z – 12 in a horizontal format. b. Write the opposite of the subtracted polynomial, then add like terms. (4z 2 + 9z – 12) – (5z 2 – z + 3) = 4z 2 + 9z – 12 – 5z 2 + z – 3 = 4z 2 – 5z 2 + 9z + z – 12 – 3 = –z 2 + 10z – 15

6. GUIDED PRACTICE for Examples 1 and 2 Find the sum or difference. 1. (t 2 – 6t + 2) + (5t 2 – t – 8) 6t 2 – 7t – 6 2. (8d – 3 + 9d 3 ) – (d 3 – 13d 2 – 4) 8d 3 + 13d 2 + 8d + 1 ANSWER

7. EXAMPLE 3 Multiply polynomials vertically and horizontally a. Multiply –2y 2 + 3y – 6 and y – 2 in a vertical format. b. Multiply x + 3 and 3x 2 – 2x + 4 in a horizontal format. SOLUTION a. –2y 2 + 3y – 6 y – 2 4y 2 – 6y + 12 Multiply –2y 2 + 3y – 6 by –2. –2y 3 + 3y 2 – 6y Multiply –2y 2 + 3y – 6 by y –2y 3 + 7y 2 –12y + 12 Combine like terms. b. (x + 3)(3x 2 – 2x + 4) = (x + 3)3x 2 – (x + 3)2x + (x + 3)4 = 3x 3 + 9x 2 – 2x 2 – 6x + 4x + 12 = 3x 3 + 7x 2 – 2x + 12

8. EXAMPLE 4 Multiply three binomials Multiply x – 5, x + 1, and x + 3 in a horizontal format. (x – 5)(x + 1)(x + 3) = (x 2 – 4x – 5)(x + 3) = (x 2 – 4x – 5)x + (x 2 – 4x – 5)3 = x 3 – 4x 2 – 5x + 3x 2 – 12x – 15 = x 3 – x 2 – 17x – 15

9. EXAMPLE 5 Use special product patterns Sum and difference = 9t 2 – 16 Square of a binomial = 64x 2 – 48x + 9 Cube of a binomial = p 3 q 3 + 15p 2 q 2 + 75pq + 125 = (3t) 2 – 4 2 = (8x) 2 – 2(8x)(3) + 3 2 = (pq) 3 + 3(pq) 2 (5) + 3(pq)(5) 2 + 5 3

10. GUIDED PRACTICE for Examples 3, 4 and 5 Find the product. 3. (x + 2)(3x 2 – x – 5) 3x 3 + 5x 2 – 7x – 10 4. (a – 5)(a + 2)(a + 6) (a 3 + 3a 2 – 28a – 60) 5. (xy – 4) 3 x 3 y 3 – 12x 2 y 2 + 48xy – 64 ANSWER

11. HOMEWORK: Pg. 341-342 #13-61 eoo and prepare for quiz on 6.2 and 6.3 by looking over Pg. 344 #13-26