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8.3 Factoring Quadratic Equations Objective The student will be able to:. Factor trinomials with grouping. Solve quadratic equations using Zero Product Property. Factoring Chart This chart will help you to determine which method of factoring to use. Type Number of Terms.
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8.3 Factoring Quadratic Equations ObjectiveThe student will be able to: Factor trinomials with grouping. Solve quadratic equations using Zero Product Property .
Factoring ChartThis chart will help you to determine which method of factoring to use.TypeNumber of Terms 1. GCF 2 or more 2. Grouping 4 • Quadratic 3 Trinomials
Review: (y + 2)(y + 4) y2 First terms: Outer terms: Inner terms: Last terms: Combine like terms. y2 + 6y + 8 +4y +2y +8 In this lesson, we will begin with y2 + 6y + 8 as our problem and finish with (y + 2)(y + 4) as our answer.
M A Product of the first and last coefficients Middlecoefficient Multiply Add+8 +6 Ex 1) Factor y2+6y + 8 Here’s your task… What numbers multiply to +8 and add to +6? If you cannot figure it out right away, write the combinations.
Multiply Add+8 +6 Ex 1) Factor y2 + 6y + 8Place the factors in the table. +9, NO -9, NO +6, YES!! -6, NO Which has a sum of +6? +1, +8 -1, -8 +2, +4 -2, -4 We are going to use these numbers in the next step!
M A Product of the first and last coefficients Middlecoefficient Multiply Add-63 -2 Ex 2) Factor x2 – 2x – 63 -62 62 -18 18 -2 2 Signs need to be different since number is negative. -63, 1 -1, 63 -21, 3 -3, 21 -9, 7 -7, 9
Replace the middle term with our working numbers.x2 – 2x – 63 x2– 9x + 7x – 63 Group the terms. (x2 – 9x) (+ 7x – 63) Factor out the GCF x(x – 9) +7(x – 9) The parentheses are the same! Weeedoggie! (x + 7)(x – 9)
4 steps for solving a quadratic equation Set = 0 Factor Split/Solve Check • Set the equation equal to 0. • Factor the equation. • Set each part equal to 0 and solve. • Check your answer on the calculator.
Ex 3) Solve: – 24a +144 = – a2 Set = 0 Factor Split/Solve Check Put it in descending order. a2 – 24a + 144 = 0 (a – 12)2 = 0 a – 12 = 0 a = 12 {12}
Set = 0 Factor Split/Solve Check Ex 4) Solve: x3 + 2x2 = 15x x3 + 2x2 – 15x = 0 x(x2 + 2x – 15) = 0 x(x + 5)(x – 3) = 0 x = 0or x + 5 = 0or x – 3 = 0 {0, – 5, 3}
Here are some hints to help you choose your factors in the MAMA table. 1) When the last term is positive, the factors will have the same sign as the middle term. 2) When the last term is negative, the factors will have different signs.