[[x]] means that the integer should be rounded down to the greatest integer that is of the same value as x or is lower than x.
Solve for k using graphed value:
96 = k6
k = 16
y = 16x
Another given value of x is 12. 12•16 = 192, so that checks out ok.
Hey there!

Your correct answer would be
. . .

Hope this helps.
~Jurgen