![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
1)
a) -(2+5) = -2 - 5 = -7
b) +(-3+6) = -3 + 6 = 3
c) (-50+3) = -50 + 3 = -47
d) -(-2+3) = 2 - 3 = -1
e) -(10-3) = -10 + 3 = -7
f) -(-3)-(-3+1) = 3 + 3 - 1 = 5
g) (-5)+(-2+10) = -5 - 2 + 10 = 3
2)
a) -50+120+(-150)-20+30
= -(50 + 20) + (120 + 30 - 150)
= -70
b) 265-70+(-65)-30+15
= (265 - 65) - (70 + 30) + 15
= 200 - 100 + 15 = 115
c) -17+185-183+(-85)-63
= (185 - 85) - (183 + 17) - 63
= 100 - 200 - 63 = -163
d) -30+60+(-170)-260+19
= -(170 + 30) - (260 - 60) + 19
= -200 - 200 + 19 = -381
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{101+100+99+...+2+1}{101-100+99-...+3-2+1}=\frac{101\left(101+1\right):2}{1+1+1+...+1+1\left(51cs1\right)}=\frac{5151}{51}=101\)
A = \(\frac{1}{10}\)+ \(\frac{1}{30}\)+\(\frac{1}{60}\)+.....+\(\frac{1}{360}\)+ \(\frac{1}{450}\)=?
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
24 = 23.3; 36 = 24.34; 60 = 22.3.5
ƯCLN( 24; 36; 60) = 22.3 = 12
12 = 22.3; 15 = 3.5; 10 = 2.5
ƯCLN(12; 15; 10) = 1
24 = 23.3; 16 = 24; 8 = 23
ƯCLN(24; 16; 8) = 23
9 = 32; 81 = 34
ƯCLN( 9; 81) = 9
11 = 11; 15 = 3.5
ƯCLN( 11; 15) = 1
1 = 1; 10 = 2.5
ƯCLN(1; 10) = 1
150 = 2.3.52; 84 = 22.3.7
ƯCLN( 150; 84) = 6
\(\frac{1}{10}+\frac{1}{30}+\frac{1}{60}+\frac{1}{100}+\frac{1}{150}\)
= \(\frac{1}{10}.\left(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}\right)\)
= \(\frac{1}{10}.2.\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\right)\)
= \(\frac{1}{5}.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\right)\)
= \(\frac{1}{5}.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\right)\)
= \(\frac{1}{5}.\left(1-\frac{1}{6}\right)\)
= \(\frac{1}{5}.\frac{5}{6}\)
= \(\frac{1}{6}\)
\(\frac{1}{10}+\frac{1}{30}+\frac{1}{60}+\frac{1}{100}+\frac{1}{150}\)
\(=\frac{1}{10}.\left(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}\right)\)
\(=\frac{1}{10}.2.\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\right)\)
\(=\frac{1}{10}.2.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\right)\)
\(=\frac{1}{10}.2.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\right)\)
\(=\frac{1}{5}.\left(1-\frac{1}{6}\right)\)
\(=\frac{1}{5}.\frac{5}{6}\)
\(=\frac{1}{6}\)
Rất vui vì giúp đc bạn <3