Răspuns:
(2+4+...+200):(4+8+...+100):13=
Explicație pas cu pas:
2+4+...+200=
=2(1+2+3+...+100)
=2*100*(100+1):2
=100*101
=10100
----------------
4+8+...+100=
=4(1+2+3+...+25)
=4*25*(25+1)/2
=2*25*26
=1300
-----------------
=> (2+4+...+200):(4+8+...+100):13=10100:1300:13=[tex]\frac{10100}{1300}:13=\frac{101}{13} *\frac{1}{13} =\frac{101}{169}[/tex]
Succes la scoala! :)
