1,8х+1,2х=2-7
3х=-5
х=-5:3
х=-1 2/3
Х2-2х+1/х2-1=(х-1)2/(х-1)(х+1)=х-1/х+1
5m2+10mn+5n2/15m2-15n2=5(m2+2mn+n2)/15(m-n)(m+n)=(m+n)2/3(m-n)(m+n)=m+n/39m-n)
<span> x+5+(4x-6)=</span><span> x+5+4x-6 =5х -1</span>
6/25*3= 2/25 (0.08)
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