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November 12th, 2016, 06:43 AM  #1 
Member Joined: Nov 2016 From: Ireland Posts: 67 Thanks: 2  Functional misunderstanding
Hi guys I'm just struggling with a few things in my maths revision. Wondering if one of you geniuses could give me a kick in the right direction. Given the function f(t) = 2t^2 + 4 find 1. f(4x+2) f(4x + 2) = 2(4x + 2)^2 + 4 = 2(16x^2 + 16x + 4) + 4 = 32x^2 + 32x + 8 + 4 = 32x^2 + 32x + 12 Ok so look at the first line of the answer  replacing the fuction t with the new function... all good. But this second line = 2(16x^2 + 16x + 4) + 4 Where is this second.................. 16x coming from? Sorry I'm obviously missing something silly guys. Last edited by Kevineamon; November 12th, 2016 at 06:53 AM. 
November 12th, 2016, 07:13 AM  #2 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,429 Thanks: 868 Math Focus: Elementary mathematics and beyond 
$$(4x+2)(4x+2)=16x^2+8x+8x+4=16x^2+16x+4$$ See? 
November 12th, 2016, 07:17 AM  #3 
Member Joined: Nov 2016 From: Ireland Posts: 67 Thanks: 2 
Doh!!! Lol thanx Greg 
November 12th, 2016, 07:17 AM  #4 
Member Joined: Nov 2016 From: Ireland Posts: 67 Thanks: 2 
Btw your signature is most applicable 

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