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joyfrancis (1504)

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Olaaa!! Perrrfect answer. 236  [398 rates]

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x2+14x+9 / x2+2x+9
= 1 + 12x/x2+2x+9
Now , just find maxima and minima of 12x/x2+2x+9
Let f(x)=12x/x2+2x+9
so f'(x) would come out to be = 108-12x2/(x2+2x+9)2 .....by quotient rule
since x2+2x+9 is always > 0 the critical points would be only where
108-12x2=0
i.e x = plusminus3
at x = 3;12x/x2+2x+9 = 3/2
at x = -3;12x/x2+2x+9 = -3
So maximum value of  x2+14x+9 / x2+2x+9 = 3/2+1=5/2
& min. value = -3+1=-2

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