How do you write direct variation equations?

Related questions

• What is Direct Variation?
• What does direct variation look like on a graph?
• What are examples of direct variation?
• How do you determine if a function is a direct variation when given a table?
• What is the constant of proportionality "k"?
• Why is `y=2x-1` not a direct variation?
• How do you graph the direct variation equation `y=-\frac{1}{6}x`?
• What is the direct variation equation if y varies directly with x, and `y=7.5` when `x=2.5`?
• What is the direct variation equation if y varies directly with x, and `y=2` when `x=4`?
• What is the constant "k" in `y=-\frac{2}{3}x`?