some text

[Y = frac{X_{A}}{X_{AB}}]

$begin{array}{l l}
     X_{A}:         & text{Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book}  \
     X_{AB}:         & text{Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old.} \
  end{array}$

some other text