One fifth of Bill's age is 4 years. Find Bill's age.
1 answer:
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Answer:
Answer:
a = - 1.1
Step-by-step explanation:
Condition for a single variable function f(x) to be decreasing is f'(x) < 0.
So, in our case, .
Then, differentiating with respect to x on both sides we get,
⇒
⇒
{Dividing both sides with - 1 and hence the inequality sign changes}
⇒
⇒ 8 > - 6x³ {Multiplying both sides with x³}
⇒ 6x³ > - 8 {Interchanging the sides}
⇒
⇒ x > - 1.1
Therefore, a = - 1.1. (Answer)