8.8: FACTORING BY GROUPING: Higher Degree Polynomials: Polynomials with a degree higher than 2. FACTORING 2 ax + bx + c Procedure: 1) Always look for the GCF of all the terms 2) Factor the remaining terms – pay close attention to the value of coefficient a and follow the proper steps. 3) Re-write the original polynomial as a product of the polynomials that cannot be factored any further. GOAL: FACTORING: By Grouping Ex: What is the FACTORED form of: 3 2 3n -12n +2n-8? SOLUTION: To factor a polynomial by grouping we group terms that have a GCF: 3 2 3 2 3n -12n +2n-8 3n -12n +2n-8 Look at GCF of each: 3 2 3n -12n 2n-8 2 3n (n-4) 2(n-4) Now take the GCF of the two: 2 3n (n-4) Factored form : +2 (n-4) 2 (n-4)(3n +2) YOU TRY IT: Ex: What is the FACTORED form of: 3 2 8t +20t+14t +35? SOLUTION: To factor a polynomial by grouping we group terms that have a GCF: 8t3+14t2+20t+35 8t3+14t2+20t+35 Look at GCF of each: 3 2 8t +14t 2 2t (4t+7) 20t+35 5(4t+7) Now take the GCF of the two: 2 2t (4t+7) Factored form : +5(4t+7) 2 (4t+7)(2t +5) YOU TRY IT: Ex: What is the FACTORED form of: 4 3 2 4q -8q +12q -24q? SOLUTION: Before we group, we must again go back to the first step of factoring: 1) Factor what is in common? 4 3 2 4q -8q +12q -24q? 3 2 4q(q -2q +3q-6) SOLUTION: To factor a polynomial by grouping we group terms that have a GCF: 4q(q3-2q2+3q-6) 4q(q3-2q2+3q-6) Look at GCF of each: 3 2 q -2q 3q-6 2 q (q-2) 3(q-2) Now take the GCF of the two: 2 q (q-2) +3(q-2) Factored form : 4q (q-2) 2 (q +3) REAL-WORLD: The area of a square rug is given by 2 4x -100. What are the possible dimensions of the rug? SOLUTION: To factor a difference of two squares with a coefficient ≠ 1 we still follow the factoring procedure: 2 ax +c 4x2-100 4(x2-25) a= +1 c =-25 Look at the factors of a and c: a : (1)(1) c: (-5)(5) We now see that the factored form is: 4(x-5)(x+5) NOW SOLVE THIS: VIDEOS: Factoring Quadratics Factoring by Grouping: http://www.khanacademy.org/math/algebra/quadratics/f actoring_quadratics/v/factoring-trinomials-with-a-non-1leading-coefficient-by-grouping Factoring by Grouping: http://www.khanacademy.org/math/algebra/quadratics/ factoring_quadratics/v/ex2-factoring-quad VIDEOS: Factoring Quadratics Factoring by Grouping: http://www.khanacademy.org/math/algebra/quadratics/f actoring_quadratics/v/factoring-trinomials-by-grouping-5 Factoring by Grouping: http://www.khanacademy.org/math/algebra/quadratics/fa ctoring_quadratics/v/factoring-trinomials-by-grouping-6 CLASSWORK: Page 514-516: Problems: 1, 2, 3, 9, 13, 16, 22, 27, 30, 32, 37, 45.