Question

Which of the following represents a direct proportional relationship between
$y$ and $x$ ?

• A. $y=3x^2$
• B. $y=2x$
• C. $y=2x^3$
• D. $y=2x^4$

Answer 1

The correct option is B $y=2x$

Let’s use an example to answer this question.
If the total cost, $y$ is proportional to the number of items, $x$ purchased at a constant price $2,$ then the direct proportional relationship between the total cost and the number of items can be expressed as $y=2x.$