Răspuns:
a=(2+4+6+..+100)-50
(2+4+6+..+100)=(1+2+3+..+50)=50•51/2=1275
1275-50=1225
==> a=1225
a²=1225
a=√1225
==> a=35
a=(2+4+6+...+100)-50
2+4+6+...+100= 2(1+2+3+...+50)=
2×50(50+1)/2= 50(50+1)=
50×51=2.550
a= 2.550-50= 2.500
[tex] \sqrt{a} = \sqrt{2500} = 50[/tex]
