Question

if y=6 when x=2/3 find x when y=12

Answer 1

y=6 x=2/3
y=12 x=?
6*2=12, 2/3*2=?
?=2*2/3
?=1 and 1/3

Answer 2

X would equal 4/3 when y equals 12. Since y is doubling you can double the other side as well. So you simply do 2/3*2, to get 4/3.