Answer:
[tex]y(x)=19*x[/tex]
Step-by-step explanation:
Given the height of 6 DVD cases, you can know the height of a single DVD case, by dividing the total height, in the number of cases ([tex]\frac{114mm}{6} = 19mm[/tex] for this problem).
Now, knowing the height of a single DVD case ([tex]19mm[/tex]), you can think the expression in this way: If I already know the height of a single case, the height of any number of cases will be the result of multiplying the height of the case by the number of cases I want to stack.
As the problem states, x is the number of cases in the stack, so, multiply the height of a single case for the number of cases (x).
This will result in the expression: [tex]y(x)=19*x[/tex]
To know the height of a stack of 13 cases, just replace x=13 in the equation you just figured: [tex]y(13)= 19* (13) = 247[/tex] , but don't forget the unit is mm, so the final result is 247 mm.
