Answer:
[tex]y=27/2\text{ or } 13.5[/tex]
Step-by-step explanation:
If y and x have a proportional relationship, then they have the standard form:
[tex]y=kx[/tex]
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:
[tex]9=2k[/tex]
Divide both sides by 2:
[tex]\displaystyle k=\frac{9}{2}=4.5[/tex]
So, our constant of proportionality is 9/2 or 4.5.
Therefore, our equation is:
[tex]\displaystyle y=\frac{9}{2}x[/tex]
To find y when x=3, substitute 3 for x and evaluate. Hence:
[tex]\displaystyle y=\frac{9}{2}(3)[/tex]
Evaluate:
[tex]\displaystyle y=\frac{27}{2}=13.5[/tex]
So, when x=3, y=27/2 or 13.5
