👤
Table
a fost răspuns

urenta coroana plus 50 puncte calculati sumele 4+8+12+.........+1996= 7+14+21+.......+3157= 8+16+24+............+2504 = 11+22+33+.......+1331 = 19+38+57+........+1995=

Răspuns :

Sanduurzica
1) 4x(1+2+3+........................+499)=
    4x[499x(499+1):2]=
    4x[499x500:2]=
    4x(249.500:2)=
    4x124.750=499.000
2) 7x(1+2+3+.........................+451)=
    7x[451x(451+1):2]=
    7x[451x452:2]=
    7x(203.852:2)=
    7x101.926=713.482
3) 8x(1+2+3+...........................+313)=
    8x[313x(313+1):2]=
    8x[313x314:2]=
    8x(98.282:2)=
    8x49.141=393.128
4) 11x(1+2+3+..........................+121)=
    11x[121x(121+1):2]=
    11x[121x122:2]=
    11x(14.762:2)=
    11x7.381=81.191
5) 19x(1+2+3+..........................+105)=
    19x[105x(105+1):2]=
    19x[105x106:2]=
    19x(11.130:2)=
    19x5.565=105.735
Alexd111ba
1996+1992+1988+------------+4
4+8+12+--------+1996
2S=2000+2000+2000+2000
4,8,12,------1996/:2
2,4,6------998/:2
1,2,3-------499/deci 499
499×2000=998000 2S
S=998000:2
S=499000