# How do you find the local max and min for #f(x) = 7x + 9x^(-1)#?

##### 1 Answer

Nov 29, 2016

To find the local extrema we find the points where the first derivative is null and study the sign of the second derivative

#### Explanation:

Find the values of

In both points

1) around

2) around

graph{7x+9/x [-47.3, 47.2, -73.6, 73.6]}