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D.O.T.S. D ifference O f T wo S quares. Perfect Squares. Difference means subtract. x 2. 9. 9x 2. So, examples of DOTS:. y 2. 16. 25y 2. a 2. 49. 81x 2 y 2. x 2 – 16. or 4a 2 – 25b 2. 4x 4 y 6. 100. b 6. D.O.T.S. D ifference O f T wo S quares.
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D.O.T.S. DifferenceOfTwoSquares Perfect Squares Difference means subtract x2 9 9x2 So, examples of DOTS: y2 16 25y2 a2 49 81x2y2 x2 – 16 or 4a2 – 25b2 4x4y6 100 b6
D.O.T.S. DifferenceOfTwoSquares DOTS always factors the same way. (Square root of the first + square root of the last) times (Square root of the first – square root of the last) Example: x2 – 16 = (x 4) (x – 4) +
D.O.T.S. DifferenceOfTwoSquares 4a2 – 25b2 = (2a + 5b) (2a – 5b) b2 – 49 = (b + 7) (b – 7) (3xy – 8b3) 9x2y2 – 64b6 = (3xy + 8b3)
D.O.T.S. FLASH CARDS Is it DOTS? x2 – y2 D
D.O.T.S. FLASH CARDS Is it DOTS? a2 – 9 D
D.O.T.S. FLASH CARDS Is it DOTS? 6m2 – 81 D Why not? 6 IS NOT A PERFECT SQUARE!
D.O.T.S. FLASH CARDS Is it DOTS? 4b2 + 25 D Why not? THIS IS A SUM OF 2 SQUARES.
D.O.T.S. FLASH CARDS Is it DOTS? 49b2 – 100c4 D
? P.S.T. Perfect Square Trinomial How to identify: ☺1st & last term must be perfect squares YES! x2 + 6x + 9 ☺Square root of the first ☺Square root of the last x 3x 3 ☺Multiply them ☺Double the result ☺Is it the same as the middle term?(disregard sign)
? P.S.T. Perfect Square Trinomial How to identify: ☺1st & last term must be perfect squares x2 + 6x + 9 THIS ☺Square root of the first ☺Square root of the last x 3x 3 IS ☺Multiply them A PST ☺Double the result ☺Is it the same as the middle term?(disregard sign)
P.S.T. FLASH CARDS Is it PST? x2 – 10x + 25 U BETCHA
P.S.T. FLASH CARDS Is it PST? x2 – 10x – 25 NO WAY DO YOU KNOW WHY?
P.S.T. FLASH CARDS Is it PST? x2 + 20x + 40 NO WAY DO YOU KNOW WHY?
P.S.T. FLASH CARDS Is it PST? 9m2 + 42m + 49 U BETCHA
P.S.T. FLASH CARDS Is it PST? x2 + 16xy + 64y2 U BETCHA
P.S.T. FLASH CARDS What would make this a PST? ±12x x2 _____ + 36
P.S.T. FLASH CARDS What would make this a PST? ±36xy 4x2 _______ + 81y2
P.S.T. FLASH CARDS What would make this a PST? + 9 x2 – 6x ____
P.S.T. Perfect Square Trinomial How to factor x2 + 6x + 9 Square root of the first (x + 3) Sign of the second term 2 Square root of the last Quantity squared
P.S.T. Perfect Square Trinomial How to factor 4m2 – 20m + 25 Square root of the first (2m – 5) Sign of the second term 2 Square root of the last Quantity squared
FLASH CARDS Factoring Practice RECALL STEPS! 5x2 + 10xy 1. CMF BINOMIAL? 2. DOTS 5x(x + 2y) TRINOMIAL 3. PST GUESS
FLASH CARDS Factoring Practice RECALL STEPS! x2 – 9y2 1. CMF BINOMIAL? 2. DOTS (x + 3y)(x – 3y) TRINOMIAL 3. PST GUESS
FLASH CARDS Factoring Practice RECALL STEPS! 4x2 – 28x + 49 1. CMF BINOMIAL? 2. DOTS (2x – 7)2 TRINOMIAL 3. PST GUESS
FLASH CARDS Factoring Practice RECALL STEPS! a2 – 2a – 15 1. CMF BINOMIAL? 2. DOTS (a – 5)(a + 3) TRINOMIAL 3. PST GUESS
FLASH CARDS Solving Equations 2x3 + 8x2 – 42x = 0 Set equal to zero: Already is! 2x(x2 + 4x – 21) = 0 Factor left side: 2x(x + 7)(x – 3) = 0 More Factoring?? Factors = to 0: 2x= 0 or x + 7 = 0 or x – 3 = 0 Solve equations: x= 0 or x = -7 or x = 3