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va rooooooooooooooog​

Va Rooooooooooooooog class=

Răspuns :

l) x/(x+1)+1/(x+1)=

=(x+1)/(x+1)=1

m) (y+1)/(y+3)+3/(y+3)+(y+2)/(y+3)=

=(y+1+3+y+2)/(y+3)=

=(2y+6)/(y+3)=

=2(y+3)/(y+3)=2

n) 2/(n+1)+4/(n+1)+6/(n+1)+....+2n/(n+1)=

=(2+4+6+....+2n)/(n+1)=

=2(1+2+3+...+n)/(n+1)=

=2×[n(n+1)/2]/(n+1)=

=n(n+1)/(n+1)=n