M ULTIPLYING P OLYNOMIALS : FOIL Lesson 10-3
M ULTIPLYING P OLYNOMIALS When multiplying two BINOMIALS… …we multiply by “FOIL” First terms Outer terms Inner terms Last terms
M ULTIPLYING P OLYNOMIALS (2 x + 1) ( x – 5) FOIL = distribution, combine like terms 2 x – 10 x + 1 x -5 2 x – 9 x -5
M ULTIPLYING P OLYNOMIALS (3 x – 5) (2 x + 7) 6 x ² + 21 x – 10 x – 35 6 x ² + 11 x – 35 ( x – 7) (3 x + 1) 3 x ² + x – 21 x – 7 3 x ² – 20 x - 7
M ULTIPLYING P OLYNOMIALS Special products: ( x – 5) ( x + 5) x ² + 5 x – 5 x – 25 x ² – 25 Special products: (2 x – 8) (2 x + 8) 4 x ² + 16 x – 16 x – 64 4 x ² – 64
M ULTIPLYING P OLYNOMIALS When multiplying a trinomial & binomial… … distribution and combine like terms (3 x ² + x – 6) (2 x – 3) (2 x – 3) (3 x ² + x – 6) 6 x ³ + 2 x ² – 12 x - 9 x ² - 3 x x ³ - 7 x ² – 15 x + 18
M ULTIPLYING P OLYNOMIALS Find the product: (3 a + 4) (5 a ² + 2 a – 3) 15 a ³ + 6 a ² - 9 a + 20 a ² + 8 a – a ³ + 26 a ² - a - 12
P RACTICE a) ( x + 2) ( x + 5) b) (2 x – 1) ( x + 2) c) ( a – 6) ( a + 6) d) ( f ² - 3 f ) ( f ² + 6 f – 4)
H OMEWORK p #14-19, 23-29, 41-43