1. **Stating the problem:** We are given a linear function describing the relationship between dollars and reals as $y = 12x$. 2. **Formula used:** The function is already given as $y = 12x$, where $y$ represents the amount in reals and $x$ represents the amount in dollars. 3. **Understanding the function:** This means for every 1 dollar, you get 12 reals. 4. **Example calculation:** If you want to find how many reals correspond to 50 dollars, substitute $x=50$ into the equation: $$y = 12 \times 50 = 600$$ 5. **Interpretation:** So, 50 dollars equals 600 reals. This linear function shows a direct proportionality between dollars and reals with a conversion rate of 12 reals per dollar.