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Function $f$ and $f^2$ are such that $f:x→hx+k$ and $f^2:x→9x+16$.

Considering $h>0$, find the values of $x$ such that $f(x^2)=8x$

so i know that $h=3$ and $k=4$

and here is what i did with it

$f(x^2)=8x$

$(3x+4)^2=8x$

$9x^2+24x+16-8x=0$

$9x^2+16x+16=0$

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    I think $f^2$ should be understood as the composition map $f°f:x\mapsto h(hx+k)+k$ – 2017-01-19
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    @JeanMarie: Yes, you're right, but the first part is irrelevant here, because it has already been solved for the OP here on MSE (http://math.stackexchange.com/questions/2103152/the-function-f-and-f2-are-such-that-fx%e2%86%92hxk-and-f2x%e2%86%929x16). – 2017-01-19

1 Answers 1

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If $f (x)=3x+4$, then $$f (x^2)=3(x^2)+4 \neq f (x)^2=(3x+4)^2$$

Can you take it from here?

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    yea, thanks for the help – 2017-01-19