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>Вот ответ: (170*5+50):10=90
</span>
D = 4+4*8=36
x^2(1) = (2+6)/2=4
x1 = -2
x2 = 2
x^2(2)= (2-6)/2=-2<0 не имеет решения
Ответ: x1 = -2, x2 = 2