Б)(1/7)∧-3х+1≥(1/49)∧х+3
(1/7)∧-3х+1≥(1/7)∧2х+6, 1/7≤1(основа меньше 1)
-3х+1≤2х+6
-3х-2х≤6-1
-5х≤5
х≥-1
в)11∧-7х+1≤121∧-2х-10
11∧-7х+1≤11∧-4х-20, 11≥1(основа больше 1)
-7х+1≤-4х-20
-7х+4х≤-20-1
-3х≤-21
х≥7
12*(-3/4)-3(5/6)=-9-2,5=-11,5
a)5a+7b-2a-8b=3a-b
b) 3(4x+2) - 5= 12x+6-5=12x+1
c) 20b-(b-3)+(3b-10)=20b-b+3+3b-10=22b-7
3х²-2х-5=0
х = -(-2)±√(-2)²-4×3×(-5) / 2×3
х = 2±√64 / 6
х = 2±8 / 6
х1 = 2+8 / 6
х2 = 2-8 / 6
х1 = 5/3
х2 = -1