ggggggggggggggggguhjycfmjgh,vj, hgj,c math
\[
\left( {\displaystyle\frac3x{y} - z} \right)^2 = \left( {\displaystyle\frac3x{y}} \right)^2 - 2\cdot\displaystyle\frac3x{y}\cdotz + z^2 = \displaystyle\frac9x^2 y^2 - \displaystyle\frac6xz {y} + z^2
\]
math