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4 tháng 4 2020
1; = ( -4/10 + 3/10 ) : ( -2/5 + 2/3 ) = -1/10 : ( -6/15 + 10/15 ) = -1/10 : 4/15 = -1/10 . 15/4 = -15/40 = -3/8
2; = 25/2 . -5/7 + 39/4 + -3/2 . 5/7 = -125/14 + 39/4 + -15/14 = ( -125/14 + -15/14 ) + 39/4 = -10 + 39/4 = -40/4 + 39/4 = -1/4
3; = 5/52 + 35/52 + 40/52 = 40/52 + 40/52 = 80/52 = 20/13
4; = ( -39/52 + 20/52 ) . 7/2 - ( 117/52 + 32/52 ) . 7/2 = -19/52 . 7/2 - 149/52 . 7/2 = ( -19/52 + -149/52 ) . 7/2 = -168/52 .7/2 = -147/13
5; = ( 36/12 + -9/12 + 8/12 ) - ( -12/6 + -8/6 + -9/6 ) - ( 6/6 - 14/6 - 27/6 ) = 35/12 + 10/12 + 70/12 = 115/12
6; = -1/3 + -8/35 +-2/9 + -1/135 +4/5 +-4/9 +3/7 = (-1/3 + -2/9 + -4/9 ) + ( -8/35 + 4/5 + 3/7 ) + -1/135 = ( -1/3 + -2/3 ) + ( -8/35 + 28/35 + 15/35 ) + -1/135 = -1 + 1 + -1/135 = -1/135
23 tháng 10 2016
Bài 1:
A = 1 + 3 + 32 + ... + 3100
=> 3A = 3 + 32 + ... + 3101
=> 2A = 3101 - 1
=> A = \(\frac{3^{101}-1}{2}\)
B = 1 + 42 + 44 + ... + 4100
=> 8B = 42 + 44 + ... + 4102
=> 7B = 4102 - 1
=> B = \(\frac{4^{102}-1}{7}\)
Bài 2:
a) S1 = 22 + 42 + ... + 202
=> S1 = 22(1+22+...+102)
=> S1 = 22.385
=> S1 = 1540
b) S2 = 1002 + 2002 + ... + 10002
=> S2 = 1002(1+22+...+102)
=> S2 = 1002.385
=> S2 = 3850000
F
5 tháng 9 2020
1) \(\left(\frac{3}{7}+\frac{1}{2}\right)^2=\left(\frac{13}{14}\right)^2=\frac{169}{196}\)
2) \(\left(\frac{3}{4}-\frac{5}{6}\right)^2=\left(-\frac{1}{12}\right)=\frac{1}{144}\)
3) \(\left(1+\frac{2}{3}-\frac{1}{4}\right)\cdot\left(\frac{4}{5}-\frac{3}{4}\right)^2\)
\(=\frac{17}{12}\cdot\left(\frac{1}{20}\right)^2=\frac{17}{4800}\)
4) \(2\div\left(\frac{1}{2}-\frac{2}{3}\right)^3=2\div\left(-\frac{1}{6}\right)^3\)
\(=2\div\left(-\frac{1}{216}\right)=-432\)
20 tháng 11 2017
a) \(\left(-\dfrac{2}{3}+\dfrac{3}{7}\right):\dfrac{4}{5}+\left(-\dfrac{1}{3}+\dfrac{4}{7}\right):\dfrac{4}{5}\)
\(=\left(-\dfrac{5}{21}\right):\dfrac{4}{5}+\left(\dfrac{5}{21}\right):\dfrac{4}{5}\)
\(=\left(-\dfrac{5}{21}+\dfrac{5}{21}\right):\dfrac{4}{5}\)
\(=0:\dfrac{4}{5}\)
\(=0\)
b) \(\dfrac{5}{9}:\left(\dfrac{1}{11}-\dfrac{5}{22}\right)+\dfrac{5}{9}:\left(\dfrac{1}{15}-\dfrac{2}{3}\right)\)
\(=\dfrac{5}{9}:\left(-\dfrac{3}{22}\right)+\dfrac{5}{9}:\left(-\dfrac{3}{5}\right)\)
\(=\dfrac{5}{9}:\left[\left(-\dfrac{3}{22}\right)+\left(-\dfrac{3}{5}\right)\right]\)
\(=\dfrac{5}{9}:\left(-\dfrac{81}{110}\right)\)
\(=-\dfrac{550}{729}\)
c) \(4^2.4^3:4^{10}\)
\(=\dfrac{4^5}{4^{10}}\)
\(=\dfrac{1}{4^5}\)
\(=\dfrac{1}{256}\)
d) \(\left(0,6\right)^5:\left(0,2\right)^6\)
\(=\dfrac{\left(0,2\cdot3\right)^5}{\left(0,2\right)^6}\)
\(=\dfrac{\left(0,2\right)^5\cdot3^5}{\left(0,2\right)^6}\)
\(=\dfrac{243}{0,2}\)
\(=1215\)
Mai mốt bạn đăng một lần ít thôi nha tại giờ khuya quá nên mình chỉ làm đến đây thôi =))
24 tháng 7 2018
mik ko bít
I don't now
................................
.............
VM
15 tháng 9 2019
1.
a) \(\left(\frac{1}{5}\right)^3.10^3\)
\(=\left(\frac{1}{5}.10\right)^3\)
\(=2^3\)
\(=8.\)
b) \(\left(-\frac{2}{5}\right)^4:2^4\)
\(=\left[\left(-\frac{2}{5}\right):2\right]^4\)
\(=\left(-\frac{1}{5}\right)^4\)
\(=\frac{1}{625}.\)
c) \(32^2:4^3\)
\(=\left(2^5\right)^2:\left(2^2\right)^3\)
\(=2^{10}:2^6\)
\(=2^4\)
\(=16.\)
d) \(\left(\frac{2}{3}\right)^4:9^2\)
\(=\left(\frac{2}{3}\right)^4:\left(3^2\right)^2\)
\(=\left(\frac{2}{3}\right)^4:3^4\)
\(=\left(\frac{2}{3}:3\right)^4\)
\(=\left(\frac{2}{9}\right)^4\)
\(=\frac{16}{6561}.\)
Chúc bạn học tốt!
15 tháng 7 2018
Ta có \(\frac{-\frac{2}{3}+\frac{3}{4}-2}{\frac{2}{3}-\frac{3}{4}-2}.\frac{-\frac{2}{3}-\frac{3}{4}-2}{\frac{2}{3}+\frac{3}{4}+2}\)
\(=\frac{-\left(\frac{2}{3}-\frac{3}{4}+2\right)}{\frac{2}{3}-\frac{3}{4}-2}.\frac{-\left(\frac{2}{3}+\frac{3}{4}+2\right)}{\frac{2}{3}+\frac{3}{4}+2}\)
\(=\frac{23}{25}.\left(-1\right)\)
\(=\frac{-23}{25}\)
20 tháng 5 2022
a: 2x-3/2+3/4=-4
=>2x-3/4=-4
=>2x=-13/4
hay x=-13/8
b: \(\left(-\dfrac{2}{3}x-\dfrac{3}{5}\right)\cdot\left(\dfrac{-3}{2}-\dfrac{10}{3}\right)=\dfrac{2}{5}\)
\(\Leftrightarrow-\dfrac{2}{3}x-\dfrac{3}{5}=\dfrac{2}{5}:\dfrac{-29}{6}=\dfrac{-2}{5}\cdot\dfrac{6}{29}=\dfrac{-12}{145}\)
=>2/3x+3/5=12/145
=>2/3x=-15/29
hay x=-45/58
c: \(\dfrac{x}{2}-\left(\dfrac{3}{5}x-\dfrac{13}{5}\right)=-\left(\dfrac{7}{10}x+\dfrac{7}{5}\right)\)
=>1/2x-3/5x+13/5=-7/10x-7/5
=>-1/10x+7/10x=-7/5-13/5
=>3/5x=-2
hay x=-2:3/5=-10/3
1/144 nhé bạn.
Chúc bạn Ht
1/114 nha bn
#Hok tốt