-5у^6/√(81у^10)=-5у^6/9•|у^5|=(-5/9)•
у^6/(-у^5)=5у/9
9a²+6a+1-4b²=(3a+1)²-(2b)²=(3a+1-2b)(3a+1+2b)
25a²-(4b²-4b+1)=(5a)²-(2b-1)²=(5a-2b+1)(5a+2b-1)
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0,01ab × 100a = a²b
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2x^2-12x-1=2-4x
2x^2-12x+4x=2+1
2x^2-12x+4x=3
2x^2-8x=3
дальше не знаю