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Can someone answer this: (1-3x)*(2+i), and also explain the FOIL system?

 Sep 20, 2017
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Can someone answer this: (1-3x)*(2+i), and also explain the FOIL system?

 

I do not usually teach this method but I shall explain it since you ask.

 

(1-3x)*(2+i)

The first bracket has 2 terms, they are                  1 and -3x

The second bracket also has 2 terms, they are     2 and   i

 

F stands for first that is 1*2 = 2

O stands for outside so that is   1*+i = i

I stands for inner                      -3x*2 = -6x

L stands for last                       -3x*i = -3xi

 

Add them all together and you have

 

\((1-3x)(2+i)\\=2+i+-6x+-3xi\\ =2+i-6x-3xi\)

 

i is often used to denote an imaginary number but since this is a low level question I assume that i is a pronumeral the same as x is.  :)

 Sep 20, 2017

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