Question

find the interval in which the following functions are strictly increasing or decerasing 6-9x-x2​

Answer 1

Step-by-step explanation:

f(x)=6−9x−x

2

f

′

(x)=−9−2x

For f to be strictly increasing f

′

(x)>0⇒2x+9<0⇒x<−

2

9

And for f to be strictly decreasing, f

′

(x)<0⇒2x+9>0⇒x>−

2

9

Hence, it is decreasing