Возможно пи/6
3,14/6≈0,523...
Cos(x/4-π/6)=-1/2
x/4-π/6=2π/3 x/4=2π/3+π/6=5π/6 x₁=10π/3
x/4-π/6=4π/3 x/4=4π/3+π/6=3π/2 x₂=6π.
Ответ: х₁=10π/3 х₂=6π.
1)12х-3у+8х+12у-30х+10у=-10х+19у
-10×2+19×(-1)=-20-19=-39
2)=13×(4,217-1,217)+0,013=13×3+0,013=39+0,013=39,013
Вот
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У=-1/4^3. у=×
у=2.2704074 ×у=×