Answer:
B) 5.57
Explanation:
When you have two fractions on either side of the equation you can do something called cross multiplication.
This is where you take the top of the fraction on the left and multiply it by the bottom of the fraction on the right, and put that equal to the bottom of the fraction on the left multipled by the top of the fraction on the right. So for example, if we had:

We could write:
ad=bc
So for our question we have:

So we can write:
14x=13(6)
Simplify:
14x=78
Divide both sides by 14 to get x by itself:

x=5.571428571
So the answer is B) 5.57