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31 tháng 5 2018
  1. A=7,2:2*28.6+1.43*2*64​=2861+3+5+7+....+49-339=984
  2. Hok tốt >>titania erza scarlet<< !!@@
31 tháng 5 2018

\(A=\frac{7,2:2\times28,6+1,43\times2\times64}{1+3+5+7+...+49-339}\)

\(A=\frac{2\times3,6\times0,5\times1,43\times4\times5+1,43\times2\times0,5\times4\times32}{\left[\left(1+49\right)\times25:2\right]-339}\)

\(A=\frac{2\times0,5\times1,43\times4\times\left(3,6\times5+32\right)}{625-339}\)

\(A=\frac{5,72\times50}{286}\)

\(A=\frac{286}{286}\)

\(A=1\)

a: Sửa đề; \(A=\dfrac{7.2:2\cdot28.6+1.43\cdot2\cdot64}{1+3+5+7+...+49-339}\) 

\(=\dfrac{3.6\cdot28.6+2.86\cdot64}{1+3+5+...+49-339}\)

\(=\dfrac{2.86\left(64+36\right)}{25^2-339}=\dfrac{286}{286}=1\)

b: =>2(x+7/8)=6*13/4=78/4=39/2

=>x+7/8=39/4

=>x=71/8

24 tháng 5 2016

a.7,2 :2 x 58,6 + 2,93 x 2 x 64

= 3,6 x 58,6 + 5,86 x 64

=210,96 + 357,04

=586

b.\(4\frac{2}{5}+2\frac{3}{7}-2\frac{2}{5}+5\frac{4}{7}\)

=\(\left(4\frac{2}{5}-2\frac{2}{5}\right)+\left(2\frac{3}{7}+5\frac{4}{7}\right)\)

= 2 + 8

= 10

c. 2 x 41 x 36 + 8 x 9 x 58 + 12 x 6

=72 x 41 + 72 x 58 + 72 x 1

=72 x ( 41 + 58 +1 )

=72 x 100

=7200

d, \(\frac{3}{5}\)x \(\frac{1}{2}\):\(\frac{2}{5}\)

=\(\frac{3}{5}\)x \(\frac{1}{2}\)x\(\frac{5}{2}\)

=\(\frac{3}{4}\)

20 tháng 7 2018

\(B=\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+...+\frac{2}{41.43}\)

\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{41}-\frac{1}{43}\)

\(=\frac{1}{3}-\frac{1}{43}\)

\(=\frac{40}{129}\)

p/s: chúc bạn học tốt

11 tháng 2 2018

\(B=\frac{1-\frac{1}{\sqrt{49}}+\frac{1}{49}-\frac{1}{\left(7\sqrt{7}\right)^2}}{\frac{\sqrt{64}}{2}-\frac{4}{7}+\frac{2^2}{7^2}-\frac{4}{343}}\)

\(B=\frac{1-\frac{1}{7}+\frac{1}{49}-\frac{1}{343}}{\frac{8}{2}-\frac{4}{7}+\frac{4}{49}-\frac{4}{343}}\)

\(B=\frac{\frac{343}{343}-\frac{49}{343}+\frac{7}{343}-\frac{1}{343}}{4-\frac{4}{7}+\frac{28}{343}-\frac{4}{343}}\)

\(B=\frac{\frac{300}{343}}{\frac{28}{7}-\frac{4}{7}+\frac{24}{343}}\)

\(B=\frac{\frac{300}{343}}{\frac{24}{7}+\frac{24}{343}}\)

\(B=\frac{\frac{300}{343}}{\frac{1323}{343}+\frac{24}{343}}\)

\(B=\frac{300}{343}:\frac{1347}{343}\)

\(B=\frac{100}{449}\)

11 tháng 2 2018

\(A=\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

\(A=\frac{2^{12}.3^5-2^{12}.3^6}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^6}{5^9.7^3+5^9.2^3.7^3}\)

\(A=\frac{2^{12}.3^5\left(1-3\right)}{2^{12}.3^5.\left(3+1\right)}-\frac{5^{10}.7^3.\left(1-7^3\right)}{5^9.7^3.\left(1+8\right)}\)

\(A=\frac{-2}{4}-\frac{5.\left(-342\right)}{9}\)

\(A=\frac{-1}{2}+\frac{1710}{9}\)

\(A=\frac{-1}{2}+190\)

\(A=\frac{-1}{2}+\frac{380}{2}\)

\(A=\frac{379}{2}\)

24 tháng 12 2023

a: \(A=\dfrac{1-\dfrac{1}{\sqrt{49}}+\dfrac{1}{49}-\dfrac{1}{\left(7\sqrt{7}\right)^2}}{\dfrac{\sqrt{64}}{2}-\dfrac{4}{7}+\left(\dfrac{2}{7}\right)^2-\dfrac{4}{343}}\)

\(=\dfrac{1-\dfrac{1}{7}+\dfrac{1}{49}-\dfrac{1}{343}}{4-\dfrac{4}{7}+\dfrac{4}{49}-\dfrac{4}{343}}\)

\(=\dfrac{1-\dfrac{1}{7}+\dfrac{1}{49}-\dfrac{1}{343}}{4\left(1-\dfrac{1}{7}+\dfrac{1}{49}-\dfrac{1}{343}\right)}=\dfrac{1}{4}\)

b: \(M=1-\dfrac{5}{\sqrt{196}}-\dfrac{5}{\left(2\sqrt{21}\right)^2}-\dfrac{\sqrt{25}}{204}-\dfrac{\left(\sqrt{5}\right)^2}{374}\)

\(=1-\dfrac{5}{14}-\dfrac{5}{84}-\dfrac{5}{204}-\dfrac{5}{374}\)

\(=1-5\left(\dfrac{1}{14}+\dfrac{1}{84}+\dfrac{1}{204}+\dfrac{1}{374}\right)\)

\(=1-5\left(\dfrac{1}{2\cdot7}+\dfrac{1}{7\cdot12}+\dfrac{1}{12\cdot17}+\dfrac{1}{17\cdot22}\right)\)

\(=1-\left(\dfrac{5}{2\cdot7}+\dfrac{5}{7\cdot12}+\dfrac{5}{12\cdot17}+\dfrac{5}{17\cdot22}\right)\)

\(=1-\left(\dfrac{1}{2}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{12}+\dfrac{1}{12}-\dfrac{1}{17}+\dfrac{1}{17}-\dfrac{1}{22}\right)\)

\(=1-\left(\dfrac{1}{2}-\dfrac{1}{22}\right)\)

\(=1-\dfrac{11-1}{22}=1-\dfrac{10}{22}=\dfrac{12}{22}=\dfrac{6}{11}\)

18 tháng 4 2018

a) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}.\frac{64}{49}\)

\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)

\(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)

\(\frac{x}{2}=\frac{117}{35}\)

\(x=\frac{117}{35}\times2\)

\(x=\frac{234}{35}\)

b) \(\frac{y}{5}+\frac{9}{2}=\frac{6}{7}.\frac{36}{49}\)

\(\frac{y}{5}+\frac{9}{2}=\frac{216}{343}\)

\(\frac{y}{5}=\frac{216}{343}-\frac{9}{2}\)

\(\frac{y}{5}=\frac{-2655}{686}\)

\(y=\frac{-2655}{686}.5\)

\(y=\frac{-13275}{686}\)

ra kết quả to quá bn ạ! Bn xem lại giúp mk nha!

11 tháng 2 2018

\(A=\dfrac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\dfrac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

\(=\dfrac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^5}-\dfrac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3\right)^3.7^3+5^9.\left(2.7\right)^3}\)

\(=\dfrac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\dfrac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.2^3.7^3}\)

= \(\dfrac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\dfrac{5^{10}.7^3\left(1-7\right)}{5^9.7^3\left(1+2^3\right)}\)

= \(\dfrac{2}{3.4}-\dfrac{5\left(-6\right)}{9}\)

= \(\dfrac{7}{2}\)

25 tháng 8 2021

mọi người giúp mình nhé

26/8/2021   at 9:00 mình nộp r

25 tháng 8 2021

a) \(49.6^4.\left(\frac{3}{2}\right)^7.\frac{1}{35}\)

\(=49.1296.\frac{2187}{128}.\frac{1}{35}\)

\(=31000.725\)

27 tháng 9 2021

5 + ( x + 27 ) = 64

      ( x + 27 ) = 64 - 5      ( x + 27 ) = 59       x             = 59 - 27       x             = 32
27 tháng 9 2021

a) \(\Rightarrow x+27=59\Rightarrow x=32\)

b) \(\Rightarrow x-2=39\Rightarrow x=41\)

c) \(\Rightarrow x+5=-322\Rightarrow x=-327\)

d) \(\Rightarrow5x=35\Rightarrow x=7\)

e) \(\Rightarrow4\left(x-5\right)=56\Rightarrow x-5=14\Rightarrow x=19\)

f) \(\Rightarrow15+x=37\Rightarrow x=22\)

g) \(\Rightarrow7\left(13-x\right)=35\Rightarrow13-x=5\Rightarrow x=8\)

h) \(\Rightarrow10\left(x+1\right)=100\Rightarrow x+1=10\Rightarrow x=9\)