Answer:
7.8655
Step-by-step explanation:
Given the functionl

Where,

We have, replacing,

We need to derivate and verify for stable equilibrum that,

Then,

Roots in,

We obtain U"(x), then we have

For
Unestable
For
Stable
Answer:
x = 13.5
Step-by-step explanation:
direct variation
y = kx
substitute x and y to find k
8 = k*6
divide by 6
8/6 =k
4/3 = k
y = 4/3 x
now put in y =18
18 = 4/3 x
multiply by 3/4
18 * 3/4 = 3/4 * 4/3 x
54/4 = x
change to a decimal
13.5 =x
Hope this helps :) picture below