239 плиз,,,,,,,,,,,,,
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X-3=5
x=5+3
x=8
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x-3=-5
x=-5+3
x=-2
ответ 8;-2
Ctg(7arcctg(-√3)+25π/4)=Ctg(7(5π/6)+6π+π/4)=Ctg(35π/6+π/4)=
=Ctg(6π-π/6+π/4)=Ctg(-2π/12+3π/12)=Ctg(π/12)=cos(π/12)/sin(π/12)=
=2cos²(π/12)/[2cos(π/12)sin(π/12)]=(1+cos(π/6))/(sin(π/6)=
=(1+√3/2)/(1/2)=2+√3
<span>1)7,3-(5,1-х)=1,8
7,3-5,1+х=1,8
х+2,2=1,8
х=1,8-2,2
х=-0,4
2)</span><span>7(6- 3Х)+6(3+2х)=57
</span><span>42-21х+18+12х=57
-9х=57-42-18
-9х=-3
9х=3
х=3/9
x=1/3
3)</span><span>11,3х - 5,2 = 1,3х + 7,4
</span><span>11,3х-1,3х=7,4+5,2
10х=12,6
х=12,6:10
х=1,26
</span>
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