1 + 3 - 5 - 7 + 9 + 11 - 13 - 15 + ... + 2013 + 2015 - 2017 - 2019
= (1 + 3 - 5 - 7) + (9 + 11 - 13 - 15) + ........ + (2013 + 2015 - 2017 - 2019)
= (- 8) + (- 8) + ......... + (- 8) có 275 số -8
= (- 8). 275
= -2200
1 + 3 - 5 - 7+ 9 + 11 - 13 - 15 + ... + 2013 + 2015 - 2017 - 2019
1 + 3 - 5 - 7 + 9 + 11 - 13 - 15 + ... + 2013 + 2015 - 2017 - 2019
TÍnh :
1 + 3 - 5 - 7 + 9 + 11 - 13 - 15 + ... + 2013 + 2015 - 2017 - 2019
3+5-7-9+11+13-15-17+19...+2013-2015-2017+2019+2020
1+2-3-4-5+6+7-8-9-10+11+12-13-14-15+...+2011+2012-2013-2014-2015+2016+2017-2018-2019-2020 giup mik v
Tính hợp lý:
A= 21.\(10^2\)-11.100+90.\(10^2\)+\(2^2\).\(5^2\).125.16
B= \(\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
C= 3+5-7-9+11+13 -13-17+19+...+2013-2015-2017+2019+2020
Làm hộ mik nha !!!
S=5-7+9-11+...+2013-2015+2017-2019
1-3-5+7+9-11-13+15+...+2017-2019-2021
1-3-5+7+9-11-13+15+...+2017-2019-2021+2023=?
