1)cos x = -1.5
∅
2)ctg x = -1
x = -π/4 + πk
1) 19+5x>=0 x>=-3.8
2)14+5x>=0 x>=-2,8
3) 2-x-x^2>=0
x^2+x-2<=0
[-2;1]
6a - (5a-(4a-3)) =
= 6a - (5a-4a+3) =
= 6а - (а + 3) =
= = 6а - а - 3 = 5а - 3