1208,
1) 2а - (3а - 4) + (5а - 1) = 2а - 3а + 4 + 5а - 1 = 4а + 3,
2) -3(а-3) - (2а+8) + 4а = -3а + 9 + 2а - 8 + 4а = 3а + 1,
3) 0,7(2-в) - (3-2в) + 1,1в = 1,4 + 0,7в - 3 + 2в + 1,1в = 3,8в - 1,6,
4) 1 5/7*(7-7/12а) - 2 2/3*(9-3/8в) = 12/7*(7-7/12а) - 8/3*(9-3/8в) =
= 12 - а - 24 + в = -12 - а + в,
1209,
1)
4(х-3) - 3(х+2) = -19,
4х-12-3х-6=-19,
х=-19+12+6,
х = -1,
2)
2,5(4-2х)-5(1-3х)=5,
10-5х-5+15х=5,
10х=5-10+5,
10х=0,
х = 0,
3)
-5(7-х)-4(х-8)=3,
-35+х-4х+32=3,
-3х=3+35-32,
-3х=6,
х=6:(-3),
х = -2,
4)
2/3(3х-1)-1/9(9х-2 1/4)=1/4,
2х-2/3-х+1/4=1/4,
х=1/4+2/3-1/4,
х = 2/3