:1)2a-11-4a+26,2)3y-2a+4y+12a-7,3)2(3x-10)-4(x+2),4)-5(2x-3y)+2(y-3x),5)-3,1(2,5m-n)-2(3m+2,1n)!

1) 2а - 11 - 4а + 26 = (2а - 4а) + (26 - 11) = - 2а + 15
2) 3у - 2а + 4у + 12а - 7 = (3у + 4у) + (12а - 2а) - 7 = 7у + 10а - 7
3) 2(3х - 10) - 4(х + 2) = 6х - 20 - 4х - 8 = (6х - 4х) - (20 + 8) = 2х - 28
4) -5(2х - 3у) + 2(у - 3х) = - 10х + 15у + 2у - 6х = (15у + 2у) - (10х + 6х) = 17у - 16х
5) -3,1(2,5m - n) - 2(3m + 2,1n) = -7,75m + 3,1n - 6m - 4,2n = -(7,75m + 6m) - (4,2n - 3,1n) = - 13,75m - 1,1n