Answer:
y = 18 when x = 3
Step-by-step explanation:
y is directly proportional to x^2, meaning:
[tex]y=ax^2[/tex]
where a is the proportion between them. We're given the values for both x and y, so plug those in and solve for a:
[tex]8=a(2)^2\\8=a4\\2=a\\a=2[/tex]
Now you can use a to solve for y when x is 3:
[tex]y=ax^2\\y=(2)(3)^2\\y=2(9)\\y=18[/tex]