Răspuns :
S = (-11)+(-10)+(-9)+.....(-1)+0+1+2+3+....+13+14 = 14+13+12 +(-11+11)+(-10+10) +
+(-9+9)+(-8+8)+(-7+7)+(-6+6)+(-5+5)+(-4+4)+(-3+3)+(-2+2)+(-1+1)+0 = 14+13+12 = 39
S = - 11 + ( - 10 ) + ( - 9 ) + ( - 8 ) + (-7 ) + ( - 6 ) + .........+ 12 + 13 + 14
S = ( - 11 + 11 ) + ( - 10 + 10 ) + ( - 9 + 9 ) + ................( - 1 + 1 ) + 12 + 13 + 14
S = 0 + 0 + ( 12 + 13 + 14 )
S = 39 ( suma)
R: 39