4/9(2 7/10у-2 1/4х)-4 1/5 (5/7у-1/2х)

4/9(2 7/10у - 2 1/4х) - 4 1/5(5/7у - 1/2х) =
= 4/9 * 27/10у - 4/9 * 9/4х - 21/5 * 5/7у + 21/5 * 1/2х =
= 6/5у - х - 3у + 21/10х =
= (1,2у - 3у) + (2,1х - х) = - 1,8у + 1.1х =
= 1,1х - 1,8у.