X= any coordinate on the x-axis . but I'm confused about the " f "
Answer:
Option C. 
Step-by-step explanation:
we know that
If two figures are similar, then the ratios of its corresponding sides is equal and its corresponding angles are congruent
so
m<A=m<J
m<B=m<K
m<C=m<L
therefore
The measure of angle J is the same that the measure of angle A

You put them in fractions then cross multiple.
18/12 and 3/x so that's 36 equals 18x then you divide 36 by 18 which is 2.