Упростить выражение
5/6(4.2x-1 1/5y)-5.4(-2/9x-1.5y)

= 5/6  ( 4 1/5х - 1 1/5у) - 5 2/5( -2/9х - 1 1/2у) == 5/6 (21/5х - 6/5у) - 27/5(-2/9х - 3/2у) == 7/2х - у  + 6/5х + 8,1у = 7/2х + 6/5х + 7,1у = = 3,5х + 1,2х + 7,1у = 4,7х + 7,1у