Ну, 5/6-1= -1/6, а 1-5/6=1/6
Больше 2
4 (3х +23) +7(6+5х) = (3+23) + (6+5) + (4+7)+х=48х
<span>0.9*(4х+3)-(1.6-0.3)=
=3.6x+2.7-1.6+0.3=
=3.6x+1.4=
=-3.6+1.4=-2.2</span>
1) 45,36/3,6=12,6 (грн.) - 1 кг конфет;
2) 12,6*6,5=81,9 (грн.)
<span>Ответ: 81,9 грн. </span>
Sinα= -3/5, π< α< 3π/2 ( III четверть)
Cosβ = 5/13, 0< β<π/2 (I четверть)
найти Cos(α+β)
Решение
Cos(α+β) =Cosα*Cosβ - Sinα*Sinβ
1) Cos²α = 1 - Sin²α = 1 - 9/25 = 16/25
Cosα = -4/5
2) Sin²β = 1 - Cos²β = 1 - 25/169 = 144/169
Sinβ = 12/13
3)Cos(α+β) =Cosα*Cosβ - Sinα*Sinβ= -4/5*5/13 - (-3/5)*12/13 =
=-20/65+ 36/65 = 16/65