Răspuns :
x+(1+2+3+4+...+49)=1625
x+(49×50:2)=1625
x+(49×25)=1625
x+1225=1625
x=1625-1225
x=400
x+(49×50:2)=1625
x+(49×25)=1625
x+1225=1625
x=1625-1225
x=400
x + (1 + 2 + 3 + ..+ 49) = 1625
x + ( 49 · 50 : 2) = 1625
x +1225 = 1625
x = 1625 - 1225
x = 400
x + ( 49 · 50 : 2) = 1625
x +1225 = 1625
x = 1625 - 1225
x = 400