We will give the formulas after the example example 3

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Unformatted text preview: x College Algebra ( ) (e) ( 2 x + 3) x 2 - x + 1 In this case the FOIL method won’t work since the second polynomial isn’t a binomial. Recall however that the FOIL acronym was just a way to remember that we multiply every term in the second polynomial by every term in the first polynomial. That is all that we need to do here. ( 2 x + 3) ( x 2 - x + 1) = 2 x3 - 2 x 2 + 2 x + 3x 2 - 3x + 3 = 2 x3 + x 2 - x + 3 [Return to Problems] Let’s work another set of examples that will illustrate some nice formulas for some special products. We will give the formulas after the example. Example 3 Multiply each of the following. (a) ( 3 x + 5 ) ( 3 x - 5 ) [Solution] (b) ( 2 x + 6 ) (c) (1 - 7 x ) 2 [Solution] 2 (d) 4 ( x + 3) [Solution] 2 [Solution] Solution (a) ( 3 x + 5 ) ( 3 x - 5 ) We can use FOIL on this one so let’s do that. ( 3x + 5 ) ( 3x - 5 ) = 9 x 2 - 15 x + 15 x - 25 = 9 x 2 - 25 In this case the middle terms drop out. [Return to Problems] (b) ( 2 x + 6 ) 2 Now recall that 42 = ( 4 ) ( 4 ) = 16 . Squari...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.

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