2sin3x>-√3
sin3x>-√3/2
-π/3+2πn<3x<4π/3+2πn
-π/9+2πn/3<x<4π/9+2πn/3
x∈(-π/9+2πn/3;4π/9+2πn/3)
1)(a+c)-(b+c)=23-(-4)
a-b=27
2)(a-b)-(a+b)=27-13
-2b=14
b=14\-2=-7
Ответ:b=-7
Удачи!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4 (3х +23) +7(6+5х) = (3+23) + (6+5) + (4+7)+х=48х