Final Answer:
If
varies directly with
and
when
, you can find the direct variation equation by using the formula
, where
is the constant of variation.
Step-by-step explanation:
In the case of direct variation, the relationship between
and
is expressed as
where
is a constant. To find the constant of variation
substitute the given values for \(y\) and \(x\) into the equation.
Given that
when

![\[12 = k * 3\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/83d7ao5p0mnf6fwrrbgyf8bvfb6e4ljot3.png)
Solving for

![\[k = (12)/(3) = 4\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/9jh5c54mcmta8higxrcajg4x1vncja51ug.png)
Now that you know
you can write the direct variation equation:
![\[y = 4x\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/7pct7p1xfsbgsofi0x4f9awahibp690ez6.png)
So, in this case, the direct variation equation is

In summary, to find the direct variation equation, substitute the given values into the
formula and solve for the constant of variation
