PN
3
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Khách
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NH
3
2 tháng 4 2017
7/9:(2+3/4.x)+5/9=23/27
7/9:(2+3/4.x)=23/27-5/9
7/9:(2+3/4.x)=8/27
2+3/4.x=7/9:8/27
2+3/4.x=21/8
3/4.x=21/8-2
3/4.x=5/8
X=5/8:3/4
X=5/6
HT
5 tháng 12 2020
\(A\frac{27^4.8^{17}}{9^6.32^3}=\frac{\left(3^3\right)^4.\left(2^3\right)^{17}}{\left(3^2\right)^6.\left(2^5\right)^3}=\frac{3^{12}.2^{51}}{3^{12}.2^{15}}=\frac{3^{12}.2^{15}.2^{36}}{3^{12}.2^{15}}=2^{36}\)
\(B=\frac{72^3.54^3:8^3}{108^5:4^5}=\frac{\left(72.54:8\right)^3}{\left(108:4\right)^5}=\frac{486^3}{27^5}=\frac{\left(3^5.2\right)^3}{\left(3^3\right)^5}=\frac{3^{15}.2^3}{3^{15}}=2^3=8\)
Bài 2
A = 2 +22 + 23 + 24 + ....+ 2100
A = ( 2+22 ) + (23 + 24 ) + ....+ (299 + 2100 )
A = 2(1+2 ) + 23 (1+2 ) + ...+ 299(1+2)
A = 2.3 + 23.3 + ....+ 299 .3
A = 3(2+23 + ...+ 299 )
=> A \(⋮\) 3 ( đpcm )
Bài 3
a, 2.3x = 312 .34 + 20 .274
2.3x = 312 . 34 + 20 . (33 ) 4
2.3x = 312 .34 + 20 .312
2.3x = 312(34+20 )
2.3x = 312 . 54
2.3x = 312 . 27 .2
2.3x = 312 . 33 .2
2.3x = 315 .2
=> x=15
b , (2x +1 ) 2 + 3.(22 + 1 ) = 22 .10
(2x +1 ) 2 + 3.(4+1 ) = 4.10
(2x +1 ) 2 + 3.5 = 40
(2x +1 ) 2 + 15 = 40
(2x +1 ) 2 = 40-15
(2x +1 ) 2 = 25
(2x +1 ) 2 = 52
=> 2x + 1 = 5
2x = 5-1
2x = 4
2x = 22
=> x=2
NM
1
3 tháng 5 2016
\(=\frac{\left(2^2\right)^3.3^5-\left(3^2\right)^2.4^3}{\left(2^2\right)^3.9^2-\left(3^2\right)^2.\left(2^3\right)^2}=\frac{4^3.3^5-3^4.4^3}{2^6.9^2-9^2.2^6}=\frac{4^3.\left(3^5-3^4\right)}{9^2.\left(2^6-2^6\right)}=\frac{162}{0}\)
phps tính không hợp lệ vì không tồn taij phân số có mẫu bằng 0
13 tháng 7 2015
\(\Rightarrow B=\frac{\frac{3}{2}.\left(\frac{1}{6}-\frac{1}{16}+\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}\right)}{\frac{33}{10}.\left(\frac{1}{6}-\frac{1}{16}+\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}\right)}=\frac{\frac{3}{2}}{\frac{33}{10}}=\frac{3}{2}:\frac{33}{10}=\frac{5}{11}\)
2 tháng 7 2020
a) Ta có: \(\frac{-1}{12}-\left(2\frac{5}{8}-\frac{1}{3}\right)\)
\(=-\frac{1}{12}-\frac{21}{8}+\frac{1}{3}\)
\(=\frac{-6}{72}-\frac{189}{72}+\frac{24}{72}\)
\(=-\frac{19}{8}\)
b) Ta có: \(-1,75-\left(\frac{-1}{9}-2\frac{1}{18}\right)\)
\(=\frac{-7}{4}+\frac{1}{9}+\frac{37}{18}\)
\(=\frac{-63}{36}+\frac{4}{36}+\frac{74}{36}\)
\(=\frac{5}{12}\)
c) Ta có: \(\frac{2}{5}+\frac{-4}{3}+\frac{-1}{2}\)
\(=\frac{12}{30}+\frac{-40}{30}+\frac{-15}{30}\)
\(=-\frac{43}{30}\)
d) Ta có: \(\frac{3}{12}-\left(\frac{6}{15}-\frac{3}{10}\right)\)
\(=\frac{3}{12}-\frac{6}{15}+\frac{3}{10}\)
\(=\frac{15}{60}-\frac{24}{60}+\frac{18}{60}\)
\(=\frac{3}{20}\)
e) Ta có: \(\left(8\frac{5}{11}+3\frac{5}{8}\right)-3\frac{5}{11}\)
\(=\frac{93}{11}+\frac{29}{8}-\frac{38}{11}\)
\(=5+\frac{29}{8}=\frac{40}{8}+\frac{29}{8}=\frac{69}{8}\)
f) Ta có: \(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)
\(=\frac{4}{9}\cdot\left(-7\right)+\frac{59}{9}\cdot\left(-7\right)\)
\(=\left(-7\right)\cdot\left(\frac{4}{9}+\frac{59}{9}\right)=\left(-7\right)\cdot7=-49\)
g) Ta có: \(\frac{-1}{4}\cdot13\frac{9}{11}-0,25\cdot6\frac{2}{11}\)
\(=\frac{-1}{4}\cdot\frac{152}{11}+\frac{-1}{4}\cdot\frac{68}{11}\)
\(=\frac{-1}{4}\cdot\left(\frac{152}{11}+\frac{68}{11}\right)=-\frac{1}{4}\cdot20=-5\)
h) Ta có: \(5\frac{27}{5}+\frac{27}{23}+0,5-\frac{5}{27}+\frac{16}{23}\)
\(=\frac{52}{5}+\frac{27}{23}+\frac{1}{2}-\frac{5}{27}+\frac{16}{23}\)
\(=\frac{52}{5}+\frac{43}{23}+\frac{1}{2}-\frac{5}{27}\)
\(=\frac{64584}{6210}+\frac{11610}{6210}+\frac{3105}{6210}-\frac{1150}{6210}\)
\(=\frac{78149}{6210}\)
i) Ta có: \(\frac{3}{8}\cdot27\frac{1}{5}-51\frac{1}{5}\cdot\frac{3}{8}+19\)
\(=\frac{3}{8}\cdot\frac{136}{5}-\frac{3}{8}\cdot\frac{206}{5}+\frac{3}{8}\cdot\frac{152}{3}\)
\(=\frac{3}{8}\cdot\left(\frac{136}{5}-\frac{206}{5}+\frac{152}{3}\right)=\frac{3}{8}\cdot\frac{110}{3}\)
\(=\frac{55}{4}\)
23 tháng 3 2018
\(c)\) \(C=\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}-\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}-\frac{3}{293}}\)
\(C=\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{193}\right)}\)
\(C=\frac{2}{3}\)
Bạn Cô nàng Thiên Bình làm đúng hết òi =.=
TX
23 tháng 3 2018
a=7.[1/8+1/27-1/49]
------------------------
11.[1/8+1/27-1/49]
=7/11
cau b,c tuong tu nha h mk
\(\frac{9^6\times16^4}{27^4\times8^3}\)
\(=\frac{(3^2)^6\times(2^4)^4}{(3^3)^4\times(2^3)^3}\)
\(=\frac{3^{12}\times2^{16}}{3^{12}\times2^9}\)
\(=\frac{2^{16}}{2^9}\)
\(=2^7\)
\(=128\)
a) \(\frac{9^6.16^4}{27^4.8^3}=\frac{\left(3^2\right)^6.\left(2^4\right)^4}{\left(3^3\right)^4.\left(2^3\right)^3}=\frac{3^{2.6}.2^{4.4}}{3^{3.4}.2^{3.3}}=\frac{3^{12}.2^{16}}{3^{12}.2^9}=\frac{3^{12}.2^9.2^7}{3^{12}.2^9}=2^7=128\)
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