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The equation of the graph is $$ y = -x^2 + 9x - 18 $$

From the graph sketched, find the range of values of $x$ for which $x^2 + 18 > 9x$.

Workings $$ y = -(x-3)(x-6) $$

I'm not sure what is the question asking ... Can I get a hint? Thanks for your help!

Björn Friedrich
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user307640
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    It is asking for what values of $x$ the expression $-x^2+9x-18$ is negative. The answer is obvious from the graph or from your factorisation. – almagest Mar 19 '16 at 19:35

1 Answers1

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Hint:

note that:

$9x<x^2-18 \iff -x^2+9x-18<0$

and look at your graph.

Emilio Novati
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