2x^2-8x=0
2x(x-4)=0
2x=0 x-4=0
x=0 x=4
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Z=(-1)²⁵(cos(π/15)+isin(π/15))²⁵=-(cos(25π/15)+isin(25π/15))=-cos(5π/3)-isin(5π/3)=-cos(2π-π/3)-isin(2π-π/3)=-cos(-π/3)-isin(-π/3)=
-cos(π/3)+isin(π/3)=-1/2+i√3/2
A)7√8 -8√(512) -√(200)=7.√(4.2)-8.√(16.32) -√(100.2)=
=7.2.√2-8.4.√(16.2)-10√2=14√2-32.4√2-10√2=
=14√2-128√2-10√2=-124√2
b)(6-√2-√18)√2=6.√2 -√2.√2-√18.√2=6√2-2-√36=
=6√2-2-6=6√2-8
c)(5-√5)²=5²-2.5.√5+(√5)²=25-10√5+5=30-10√5