Can you help with this problem?

I'm assuming that this is :

 [5x ] / [-5x^2y]  * [4] / [-xy]  * [ y^2] / [ 2y ]    =

[ -1 ] /  [ xy ]  *  [4 ] / [ -xy ] *  [ y / 2 ] =

[ -1 * 4 * y ] / [ xy * -xy * 2 ]  =

[ -4 y ] / [ - 2x^2y^2 ]  =

[ 2 ] / [ x^2 y ]