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anonymous
 4 years ago
Choose the correct product of (5x + 4)2.
25x2 + 40x + 16
25x2 − 16
25x2 + 16
25x2 − 40x + 16
anonymous
 4 years ago
Choose the correct product of (5x + 4)2. 25x2 + 40x + 16 25x2 − 16 25x2 + 16 25x2 − 40x + 16

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anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0(5x+4)(5x+4) Do you know how to use the FOIL method?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0First, Outer, Inner, Last. Your first terms that you need to multiply are 5x and 5x 5x*5x = 25x^2 Your outer terms that you need to multiply are 5x and 4. 5x*4 = 20x Your inner terms that you need to multiply are 5x and 4. 5x*4 = 20x You last terms that you need to multiply are 4 and 4. 4*4 = 16 So you have 25x^2, 20x, 20x, and 16 that you need to "combine." 25x^2 +20x +20x +16 = 25x^2 +40x +16

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0ah wow thanks so much!

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Watch this :) http://www.youtube.com/watch?v=Twtdsp0a1Iw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@phi @CrazyMexican816

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i still dont nderstand @phi

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i dont know anything?

phi
 one year ago
Best ResponseYou've already chosen the best response.1see Khan's vide if you have time http://www.khanacademy.org/math/algebra/multiplyingfactoringexpression/multiplyingbinomials/v/multiplyingbinomials

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i know that \(\color{lime}{\huge\ (5x+4)^2~}\) = 25x^2+16 but i dont understand if i add a 40x

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0in FOIL i use 5x^2+4^2 but dont get why did they add a 40x?

phi
 one year ago
Best ResponseYou've already chosen the best response.1do you know what you get when you multiply a(x+y)

phi
 one year ago
Best ResponseYou've already chosen the best response.1yes. now what if a was "complicated" in other words, if a was shorthand for (c+d) ? we would get (c+d)x + (c+d)y (I just replaced "a" with its equivalent (c+d) ) now we do the "distributive property" again: (c+d)x is the same as x(c+d), or, xc +xd and (c+d)y is cy + dy

phi
 one year ago
Best ResponseYou've already chosen the best response.1in other words (c+d)(x+y) can be written as xc + xd +yc +yd we get FOUR terms (which would come from using FOIL, if you learn that)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0foil is first out inner last

phi
 one year ago
Best ResponseYou've already chosen the best response.1with (5x+4)(5x+4) we will get 4 terms, but we can combine two of the terms, and get 3 terms in the end

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0BTW i hope you dont ge confused cuz it looks like (5x + 4)•2 but it is (5x + 4)^2

phi
 one year ago
Best ResponseYou've already chosen the best response.1let's use the distributive idea to do (5x+4)(5x+4) First, let a= (5x+4) so it's easier to see what we are doing: a(5x+4)= a*5x +a*4 now replace a with (5x+4) (5x+4)*5x + (5x+4)*4 now expand both terms: can you do that ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.05x(5x+4)+4(5x+4) 25x^2•20x+20x+16 ohhhhhh thx @phi

phi
 one year ago
Best ResponseYou've already chosen the best response.1the first part 5x(5x+4) is written as 25x^2 +20x so you get all together \[ 25x^2 +20x +20x +16\] the last step is notice we have 20 x's plus 20 more x's which is 40 x's. we write \[ 25x^2 +40x +16\]
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