Question

For the data in the table, does y vary directly with x? If it does, write an equation for the direct variation.
X Y
4 6
8 12
10 15

Answer 1

In direct variations, Y/X (or X/Y) has always the same value for all the coordinate pairs.
Example:
X Y
2 4
1 2
0 0
3 6
Y/X = 2 in all cases, so it is a direct variation.
To find the rule (equation), we assume y=kx (k is the constant 2 in the example).
So y=2x is the rule.
Now you can try this method with your question in hand.