Answer:
It does not show variation
Step-by-step explanation:
Given

Required
Determine if there's direct variation between x and y
The general form of direct variation is:

Make y the subject of formula in the given parameters;


Compare
to 
<em>Since they are not of the same form, then the given equation do not show direct variation</em>
Answer:
mini disc diameter:disc diameter
14cm:21cm = 7:10.5 = 3.5:5.25 = 1:1.5
The given inequality is:

This inequality can be divided in two parts as:
a)

b)

Solving part a:

Solving part b:

Therefore, the solution to the given inequality is

and

. Combining both the ranges we get the solution:

.
In interval notation, this solution can be expressed as [1,5]