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anonymous
 one year ago
PLEASE HELP!!!
Let f(x) = 3x^2 – x + 2 and g(x) = 5x2 – 1. Find f(g(x)).
anonymous
 one year ago
PLEASE HELP!!! Let f(x) = 3x^2 – x + 2 and g(x) = 5x2 – 1. Find f(g(x)).

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@ganeshie8 @robtobey

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0is it 5x^21 or 5x=21?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0sorry it's g(x) = 5x^2  1

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0are you looking for where they intersect

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0no I'm looking for f(g(x))

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I'm not sure, which is why I need help

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2take your function, \(f(\color{red}{x}) = 3\color{red}{x^2}\color{red}{x}+2\) and replace every red colored x with \(\color{red}{5x^21}\)

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2Simplify that and you will have \(f(g(x))\)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay, let me work this out

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2There was a typo, haha. \[f(g(x)) = 3(5x^21)^2 (5x^21) +2\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Refer to the attachment from the Mathematica program.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay, I think I worked it out. is the answer f(g(x)) = 25x^4  6 ?!?!

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2\[f(g(x)) = 3( 24x^410x^2+1) 5x^2+1+2\]\[f(g(x)) = 72x^4 30x^2+35x^2+3\]\[f(g(x))= 72x^4(30+5)x^2+6\]\[\boxed{\color{red}{f(g(x)) = 72x^4 35x^2+6}}\]

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2I think you made a mistake expanding \((5x^21)^2\)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0wait, how did you get from f(g(x))=3(5x^2−1)^2−(5x^2−1)+2 to f(g(x))=3(24x^4−10x^2+1)−5x^2+1+2

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2I expanded \((5x^21)^2\) Think of \(a=5x^2\) and \(b=1\). Now do you recall the form \(ax^22ab+b^2\)? This is the expansion of a polynomial in the form \((ab)^2\)

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2Are you with me so far?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh. but then shouldn't it be f(g(x)) = 75x^4  30x^2 + 3 − 5x^2 + 1 + 2 instead of having 72x^4?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0f(g(x)) = 3(5x^2  1)^2  (5x^2  1) + 2 f(g(x)) = 3(25x^4  10x^2 + 1)  (5x^2  1) + 2 f(g(x)) = 75x^4  30x^2 + 3  5x^2 + 1 + 2 f(g(x)) = 72x^4  35x^2 + 6

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2Oh yes it was my fault. I found it. I wrote 24 instead of 25. You are right. It should be 75 ^^

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2\[f(g(x)) = 3( \color{blue}{24x^4}10x^2+1) 5x^2+1+2\] SO when I was solving it I got 72x\(^4\) instead of 75x\(^4\)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh, so the answer is f(g(x)) = 75x^4  35x^2 + 6?

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.2Good job on spotting that error.
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