Q8 of 78 Page 13

Mark the correct alternative in the following:

For what values of x is the rate of increase of x3 – 5x2 + 5x + 8 is twice the rate of increase of x?


Let P(x)=x3-5x2+5x+8 – (1)

Given that , We have to calculate x


Differentiating (1) with respect to t, we get



3x2-10x+5=2


⇒ 3x2-10x+3=0


Factorizing the above quadratic equation, we get


(3x-1)(x-3)=0


⇒ or x=3

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