I need an equation to know what your talking about
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Answer:

Step-by-step explanation:
Given: Direct Variation
(0,0) ,(3,12),(9,36)
Required
Constant of Variation
Provided that the given data is a direct variation, the constant variation is represented by r.
r is calculated as thus;

Divide both sides by x

Point (0,0) is the center of origin and cannot be used
When x = 3, y = 12
and


When x = 3, y = 12
and


Notice that the value of r remain constant in both cases; Hence, the constant of variation is; 
1. vertical angles, so 2x=74, x=37
2. vertical angles, so 126=x+77, x=126-77=49
3. (6x-21) vertical to 105,
so 6x-21=105
6x=126
x=63
4. 8x vertical to (55+85)
8x=140
x=17.5