Algebra 2 cc Section 2.2 Solve quadratic equations by factoring Note: 3∙2 = 6, so 2 and 3 are factors of 6 Factoring is the inverse of multiplying . There are several factoring techniques. Factor out the greatest common factor (GCF) 2x2+ 6x 6x3+ 12x2 22x3 - 11x2 + 33x 21y - 7
Difference of Squares Factoring Pattern a2- b2 = (a+b)(a-b) (conjugates) Factor x2 – 9 4x2 - 25 81 – 16y2 5x2 - 20 2u2 + 8u
ax2 + bx + c is a quadratic trinomial Note: (x+2)(x+3) = x2 + 5x + 6, so (x+2) and (x+3) are factors of x2 + 5x + 6 Its factors are in the form (rx+p)(sx+q) where r∙s = a and p∙q = c, and rq+ps = b http://www.youtube.com/watch?v=AMEau9OE6Bs&feature=player_detailpage ax2 + bx + c is a quadratic trinomial Factor x2 + 4x + 3 (x+3)(x+1) x2 - 7x + 10 (x-2)(x-5)
Factor x2 - x – 6 (x-3)(x+2) x2 + 2x – 8 (x+4)(x-2)
Factor 2x2 + 4x + 2 2(x2 + 2x + 1) 2(x+1)(x+1) 3x2 - 17x + 10 (3x – 2)(x – 5) 12x2 - 25x – 7 (4x + 1)(3x – 7)
A Quadratic Equation takes the form: ax2 + bx + c = 0 It has two solutions. Solve x2 - 3x - 4 = 0 To solve a quadratic equation by factoring: Set in standard form ax2 + bx + c = 0 Factor the quadratic Set each factor equal to zero Solve each resulting equation Check solution
Solve k2 + 24k + 144 = 0 2y2 – 4y - 8 = -y2 + y
solve -3b2 + 90 = -3b
assignment Page 260 Problems 65-78 all