1*2*3+2*3*4+3*4*5+....+97*98*99+98*99*100 = ?
x : 3 + 1 - 2 + 3 - 4 + 5 - 6 + ...... + 97 - 98 + 99 = 127
X|3+1-2+3-4+5-6+...+97-98+99=127
1/2 +2/3 +3/4 +4/5+..+99/100
1/99+2/98 +3/97+...+98/2+99/1
help me,ai giải nhanh nhất tớ tick cho
tính nhanh (2/3+3/4+5/6+...+99/100).(1/2+2/3+3/4+...+98/99)-(1/2+1/3+...+99/100).(2/3+2/4+...+98/99)
tim x
x : 3 + 1 - 2 + 3 - 4 + 5 - 6 + .......... + 97 - 98 + 99 = 127
1-2+3-4+5-6+7-8+................+97-98+99
Find x , if
x : 3 + 1 - 2 + 3 - 4 + 5 - 6 + ... + 97 - 98 + 99 = 127
1+2-3-4+5+6-7-8+...+97+98-99-100+101