Х÷3=15/23-8/23
х÷3=7/23
х=7/23×3=21/23
х=21/23
Log(3) (7-4x) < 3
log(3) (7-4x) < 3
log(3) (7 - 4x) < log(3) 27
7 - 4x < 27
7 - 4x > 0
x > -5
ОДЗ: x < 1,75
№2
(0,25в)(0,8с) = 0,2вс
(7а-3)-(8-2а) = 7а-3-8+2а = 9а-11
-2(0,5х-1,4у)+2х+3,2у = -х+2,8у+2х+3,2у = 3х+6у = 3(х+2у)
№3
4-0,5(х+9) = -2,1
4-0,5х-4,5 = -2,1
-0,5х = -2,1-4+4,5
-0,5х = -1,6
х = 3,2
№!
-3,1+(-2,8-4,1)-(7/3 - 5/6) = -10-(14/6-5/6) = -10-9/6 = -60/6 - 9/6 = -69/6 = -11 3/6 = -11 1/2 = -11,5