![](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)
P = 1 + ( 22 + 23 ) + ( 24 + 25 ) + ( 26 + 27 )
P = 1 + 2 . ( 1 + 2 ) + 2 . ( 1 + 2 ) + 2 . ( 1 + 2 )
P = 1 + 2 . 3 + 2 . 3 + 2 . 3
Mỗi cặp đều có số 3
=> P = 1 + 22 + 23 + 24 + 25 + 26 + 27 chia hết cho 3
\(P=1+2^2+2^3+2^4+2^5+2^6+2^7\)
\(P=1+\left(2^2+2^3\right)+\left(2^4+2^5\right)+\left(2^6+2^7\right)\)
\(P=1+2^2\left(1+3\right)+2^4\left(1+2\right)+2^6\left(1+2\right)\)
\(P=1+2^2.3+2^4.3+2^6.3\)
\(P=\left(1+2^2+2^4+2^6\right).3⋮3\left(đpcm\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
2 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29
= (2 + 22 + 23) + (24 +25 + 26) +(27 + 28 + 29)
= (2 + 22 + 23) + 23(2 + 22 + 23) + 26(2 + 22 + 23)
= 14 + 23.14 + 26.14
= 14(1 + 23 + 26) chia hết cho 7 (ĐPCM)
![](https://rs.olm.vn/images/avt/0.png?1311)
(\(\dfrac{2}{3}\) - \(\dfrac{11}{7}\) + \(\dfrac{13}{5}\)) - (5 - \(\dfrac{4}{7}\) + \(\dfrac{6}{5}\)) - (\(\dfrac{11}{3}\) - \(\dfrac{3}{5}\))
= \(\dfrac{2}{3}\) - \(\dfrac{11}{7}\) + \(\dfrac{13}{5}\) - 5 + \(\dfrac{4}{7}\) - \(\dfrac{6}{5}\) - \(\dfrac{11}{3}\) + \(\dfrac{3}{5}\)
= (\(\dfrac{2}{3}\) - \(\dfrac{11}{3}\)) - (\(\dfrac{11}{7}\) - \(\dfrac{4}{7}\)) + (\(\dfrac{13}{5}\) - \(\dfrac{6}{5}\)+ \(\dfrac{3}{5}\))
= \(\dfrac{-9}{3}\) - \(\dfrac{7}{7}\) + (\(\dfrac{7}{5}\) + \(\dfrac{3}{5}\)) - 5
= - 3 - 1 + 2 - 5
= - (3 + 1) - ( 5 - 2)
= - 4 - 3
= - 7
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,\dfrac{1}{3}-\left(-1\dfrac{2}{5}\right)+\left(-3\dfrac{1}{4}\right)\\ =\dfrac{1}{3}-\left(-\dfrac{7}{5}\right)-\dfrac{13}{4}\\ =\dfrac{1}{3}+\dfrac{7}{5}-\dfrac{13}{4}\\ =\dfrac{20}{3\times20}+\dfrac{7\times12}{5\times12}-\dfrac{13\times15}{4\times15}\\ =\dfrac{20+84-195}{60}\\ =\dfrac{-91}{60}\)
\(b,\dfrac{5}{4}-\left(-3\dfrac{1}{2}\right)-\dfrac{7}{10}\\ =\dfrac{5}{4}+\dfrac{7}{2}-\dfrac{7}{10}\\ =\dfrac{5\times5}{4\times5}+\dfrac{7\times10}{2\times10}-\dfrac{7\times2}{10\times2}\\ =\dfrac{25+70-14}{20}\\ =\dfrac{81}{20}\)
\(c,\dfrac{3}{2}-\left[\left(-\dfrac{4}{7}-\left(\dfrac{1}{2}+\dfrac{5}{8}\right)\right)\right]\\ =\dfrac{3}{2}-\left[-\dfrac{4}{7}-\left(\dfrac{4}{8}+\dfrac{5}{8}\right)\right]\\ =\dfrac{3}{2}-\left(-\dfrac{4}{7}-\dfrac{9}{8}\right)\\ =\dfrac{3}{2}+\dfrac{4}{7}+\dfrac{9}{8}\\ =\dfrac{3\times28}{2\times28}+\dfrac{4\times8}{8\times7}+\dfrac{9\times7}{8\times7}\\ =\dfrac{84+32+63}{56}\\ =\dfrac{179}{56}\)
`@` `\text {Ans}`
`\downarrow`
`a,`
\(\dfrac{1}{3}-\left(-1\dfrac{2}{5}\right)+\left(-3\dfrac{1}{4}\right)\)
`= 1/3+7/5 - 13/4`
`= 26/15 - 13/4`
`= -91/60`
`b,`
\(\dfrac{5}{4}-\left(-3\dfrac{1}{2}\right)-\dfrac{7}{10}\)
`= 5/4+7/2 - 7/10`
`= 1,25 + 3,5 - 0,7`
`= 4,75 - 0,7`
`= 4,05`
`c,`
\(\dfrac{3}{2}-\left[\left(-\dfrac{4}{7}\right)-\left(\dfrac{1}{2}+\dfrac{5}{8}\right)\right]\)
`= 3/2 - [(-4/7) - 9/8]`
`= 3/2 - (-95/56)`
`= 179/56`
![](https://rs.olm.vn/images/avt/0.png?1311)
\(10^3.100^2.1000^5\)
=\(10^3.10^5.10^{15}\)
=\(10^{23}\)
b) \(16.64.8^2:\left(4^3.2^5.16\right)\)
=\(2^4.2^6.2^6:\left(2^6.2^5.2^4\right)\)
=\(2^{10}.2^6:\left(2^{11}.2^4\right)\)
=\(2^{16}:2^{15}\)
=2
c) \(\left(20.2^4+12.2^4-48.2^2\right):8^2\)
= \(\left[2^4.\left(20+12\right)-48.2^2\right]:8^2\)
= \(\left[16.32-48.4\right]:64\)
= \(\left[512-192\right]:64\)
= \(320:64\)
= \(5\)
Câu d thì mình chưa hiểu đề bài thì bạn viết lại hộ mình để mình giải cho
54.42-72.23=252.42-49.8
=1002-392
=10000-392=9708