Please Help!! The variables y and x have a proportional relationship, and y = 9 when x = 2. What is the value of y when x = 3? Enter your answer in the box.

Question

asked Nov 9, 2021 149k views

1 Answer

Patrick Bard · Answer 1 · 2021-11-13T18:20:38+0000

Answer:

$y=27/2\text{ or } 13.5$

Explanation:

If y and x have a proportional relationship, then they have the standard form:

y=kx

Where k is the constant of proportionality.

We know that y=9 when x=2. So, we can solve for our k. Substitute 9 for y and 2 for x. Hence:

9=2k

Divide both sides by 2:

$\displaystyle k=(9)/(2)=4.5$

So, our constant of proportionality is 9/2 or 4.5.

Therefore, our equation is:

$\displaystyle y=(9)/(2)x$

To find y when x=3, substitute 3 for x and evaluate. Hence:

$\displaystyle y=(9)/(2)(3)$

Evaluate:

$\displaystyle y=(27)/(2)=13.5$

So, when x=3, y=27/2 or 13.5