Question

Which of the following is an example of direct variation?

A) y = -1/2x
B) y = 1/2xz
C) xy = 20
D) y = 5/x

Answer 1

The correct answer to the question of which equation illustrates direct variation is A) y = -1/2x, as it fits the form y = kx, where k is the constant of proportionality.

Step-by-step explanation:

The student asked which of the following equations illustrates direct variation: A) y = -1/2x B) y = 1/2xz C) xy = 20 D) y = 5/x. The concept of direct variation is when one variable changes directly in proportion to another. In mathematical terms, this is often written as y = kx, where k is the constant of proportionality and does not equal zero. With this definition, the correct answer is A) y = -1/2x because it fits the form of y = kx with k equal to -1/2 and indicates that y varies directly with x.