Does the equation below represent a direct proportion?

[tex]\[ x = 9y \][/tex]

If yes, identify the constant of proportionality.

A. Yes, \(\frac{1}{9}\)

B. No

C. Yes, -9

D. Yes, 3



Answer :

To determine if the equation \( x = 9y \) represents a direct proportion and to identify the constant of proportionality, we should first isolate the variable \( y \).

1. Start with the given equation:

[tex]\[ x = 9y \][/tex]

2. To isolate \( y \), divide both sides of the equation by 9:

[tex]\[ \frac{x}{9} = \frac{9y}{9} \][/tex]

3. Simplify the right side:

[tex]\[ \frac{x}{9} = y \][/tex]

4. Rearrange the equation to show \( y \) explicitly in terms of \( x \):

[tex]\[ y = \frac{x}{9} \][/tex]

The equation \( y = \frac{x}{9} \) indeed represents a direct proportion, as \( y \) is directly proportional to \( x \).

The constant of proportionality is the factor by which \( x \) is multiplied to obtain \( y \). In this case, \( y = \frac{1}{9} x \), so the constant of proportionality is:

[tex]\[ \frac{1}{9} \approx 0.1111111111111111 \][/tex]

Therefore, the correct answer is:

Yes, [tex]\(\frac{1}{9}\)[/tex]