The correct next step Amy could take is to factor (x^2 - 16) on the left side of the equation to yield (x + 4)(x – 4)(x + 2) = 0.
The equation is given as:

The possible next steps are:
1. Expand the equation as follows

2. Express x^2 -16 as a difference of two squares as follows

However, the correct step in this case is to factor x^2 - 16 as a difference of two squares to give 
This is so, because the question says Amy is trying to solve for variable x.
This step will ensure that she gets the possible values of x, unlike expanding the whole equation .
Hence, the correct next step is 
Read more about equations at:
brainly.com/question/7674413
If you would like to write x = 1/3 * y in general form, you can do this using the following steps:
The general form of the equation is: ax + by + c = 0.
x = 1/3 * y
x - 1/3 * y = 0
The correct result would be x - 1/3 * y = 0.
For lines to be parallel, they have to have the same slopes. For the equation given as Ax + By + C = 0, the slope is -A / B. Equating the slopes of the given equations of lines,
- (3 / -5) = - (2 / k)
The value of k is equal to -10/3.