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X+y
x(2y-z)
a*b=13
x=y
a>c на 7
x>3y
1) Cos5π/3 = Cos(2π - π/3) = Cosπ/3 = 1/2
2) tg(- 5π/6) = - tg(π - π/6) = tgπ/6 = 1/√3 = √3/3
3) tgπ*ctgπ/4 + Cosπ/2*Sin(-2π/3) = 0*1- 0*Sin2π/3 = 0
4) Sin150° - Cos720° + tg225° = Sin(180 - 30) - Cos(2*360 +0) + tg(270 - 45) =
= Sin30° - Cos0 + ctg45°= 1/2 - 1 + 1 = 1/2 = 0,5
3х-10=2+30+14
3х-24х=10+2+30
-19х=42
х=42/-19
х=2,2
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