1.3.5+3.5.7+5.7.9+...+97.99.101
=(101-2).(101-1).101.(101+1):4
=25497450
1.3.5+3.5.7+5.7.9+...+97.99.101
=(101-2).(101-1).101.(101+1):4
=25497450
Tính C=1.3.5-3.5.7+5.7.9-7.9.11+...-97.99.101
Tính A = 1.3.5 + 3.5.7 + 5.7.9 + .... + 95.97.99 + 97.99.101
1.3.5 - 3.5.7 + 5.7.9 - ... +97.99.101 = ?
Tính:
\(\frac{2.6.10+6.10.14+10.14.18+...+194.198.202}{1.3.5+3.5.7+5.7.9+...+97.99.101}\)
Rút gọn 2.6.10+6.10.14+10.14.18+...+194.198.202/1.3.5+3.5.7+5.7.9+...+97.99.101
2.6.10+10.14. 18 +14.18.22+....+194.198.202 =?
1.3.5+3.5.7+5.7.9+....+97.99.101 = ?
Rút rọn A =\(\frac{2.6.10+6.10.14+10.14.18+........+194.198.202}{1.3.5+3.5.7+5.7.9+........+97.99.101}\)
1. TÝnh B = 1.3^2 + 3.5^2 + 5.7^2 + … + 97.99^2
2 C = 1.3.5 – 3.5.7 + 5.7.9 – 7.9.11 + … - 97.99.101
Rút gọn A=\(\frac{2.6.10+6.10.14+10.14.18+...+194.198.202}{1.3.5+3.5.7+5.7.9+...+97.99.101}\) ta được A=...........