Thực hiện phép tính:
a. A=\(\dfrac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}\)
b. B=\(\dfrac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
K
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8 tháng 10 2017
Ta có: \(B=\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}=\frac{5^2.\left(2.3\right)^{11}.\left(4^2\right)^2+\left(2.3\right)^2.\left(2^2.3\right)^6.\left(3.5\right)^2}{2.\left(2.3\right)^{12}.\left(2.5\right)^4-\left(3^4\right)^2.\left(2^6.3.5\right)^3}\)
\(\frac{5^2.2^{11}.3^{11}.2^8+2^2.3^2.2^{12}.3^6.3^2.5^2}{2.2^{12}.3^{12}.2^4.5^4-3^8.2^{18}.3^3.5^3}=\frac{5^2.2^{19}.3^{11}+2^{14}.3^{10}.5^2}{2^{17}.3^{12}.5^4-3^{11}.2^{18}.5^3}\)
\(=\frac{5^2.2^{14}.3^{10}.\left(2^5.3+1\right)}{2^{17}.3^{11}.5^3.\left(3.5-2\right)}=\frac{2^{14}.3^{10}.5^2.97}{2^{17}.3^{11}.5^3.13}=\frac{1.1.1.97}{2^3.3.5.13}=\frac{97}{1560}\)
M
8 tháng 10 2017
\(B=\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}\)
\(B=\frac{5^2.2^{11}.3^{11}.2^{4^2}+2^2.3^2.2^{2^6}.3^6.3^2.5^2}{2.2^{12}.3^{12}.10^4-3^{4^2}.2^{5^3}.3^3}\)
\(B=\frac{5^2.2^{11}.2^8.3^{11}+2^2.2^{12}.3^2.3^6.3^2.5^2}{2^{13}.3^{12}.10^4-3^8.3^3.2^{15}}\)
\(B=\frac{5^2.2^{19}.3^{11}+2^{14}.3^{10}.5^2}{2^{13}.3^{12}.10^4-3^{11}.2^{15}}\)
\(B=\frac{5^2.2^{14}.3^{10}.\left(2^5.3+1\right)}{2^{13}.3^{11}.\left(3.10^4-2^2\right)}\)
\(B=\frac{5^2.2^{14}.3^{10}.97}{2^{13}.3^{11}.29996}\)
\(B=\frac{5^2.2.97}{3.29996}\)
\(B=\frac{4850}{89988}\)
\(B=\frac{2425}{44994}\)
O
2
21 tháng 7 2016
http://olm.vn/hoi-dap/question/425436.html
21 tháng 7 2016
\(\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}=\frac{5^2.6^{11}.6^2.6^2.6^6.2^6.3^2.5^2}{2.2^{12}.3^{12}2^4.5^4-3^8.2^{15}.3^3}=\frac{5^6.6^{21}.2^8.3^2}{2^{17}.3^{12}.5^4-3^{11}.2^{15}}=\frac{5^6.3^{23}.2^{29}}{3^{11}.2^{15}.\left(2^2.3.5^4-1\right)}=\frac{5^6.3^{13}.2^{14}}{2^2.3.5^4-1}\)
P
2
T
31 tháng 12 2017
Ta có:
\(\frac{5^2.6^{11}.16^6.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}\Leftrightarrow\frac{5^2.6^{11}.16^6.12^2.15^2}{2.6^{11}.6.10^4-81^2.960^3}\)
\(\Leftrightarrow\frac{5^2.16^6.12^2.15}{2.6.10^4-81^2.960^3}\Leftrightarrow\frac{5^2.16^2.12.12.15}{\left(2.6\right).10^4-81^2.960^3}\)
\(\Leftrightarrow\frac{5^2.16^2.12.12.15}{12.10^4-81^2.960^3}\Leftrightarrow\frac{5^2.16^2.12.15}{10^4-81^2.960}\)
\(\Leftrightarrow\frac{5^2.16^2.12.3.5}{10^4-3^8.960}\Leftrightarrow\frac{5^2.16^2.12.3.5}{10^4-3^7.3.960}\Leftrightarrow\frac{5^2.16^2.12.5}{10^4-3^7.960}\)
Ps: Không chắc chắn đúng! Thầy cũng cho mình làm bài này hôm nay. Mình cũng làm cách tương tự như trên nhưng chưa biết đúng hay sai! Bạn thông cảm
31 tháng 12 2017
làm cách trình bày ra nhé biết kết quả là \(\frac{388}{7199}\)
TG
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NT
1
a: \(A=\dfrac{5^2\cdot3^{11}\cdot2^{11}\cdot2^8+3^2\cdot2^2\cdot2^{12}\cdot3^6\cdot3^2\cdot5^2}{2\cdot2^{12}\cdot3^{12}\cdot2^4\cdot5^4-3^8\cdot960^3}\)
\(=\dfrac{5^2\cdot3^{11}\cdot2^{19}+3^{10}\cdot2^{14}\cdot5^2}{2^{17}\cdot3^{12}\cdot5^4-3^{11}\cdot2^{18}\cdot5^3}\)
\(=\dfrac{5^2\cdot2^{14}\cdot3^{10}\left(3\cdot2^5+1\right)}{2^{17}\cdot3^{11}\cdot5^3\left(3\cdot5-2\right)}=\dfrac{1}{5}\cdot\dfrac{1}{8}\cdot\dfrac{1}{10}\cdot\dfrac{97}{13}=\dfrac{97}{5200}\)
b: \(B=\dfrac{2^{12}\cdot3^{10}+2^9\cdot3^9\cdot2^3\cdot3\cdot5}{2^{12}\cdot3^{12}-2^{11}\cdot3^{11}}\)
\(=\dfrac{2^{12}\cdot3^{10}\cdot\left(1+5\right)}{2^{11}\cdot3^{11}\left(2\cdot3-1\right)}=\dfrac{2}{3}\cdot\dfrac{6}{5}=\dfrac{12}{15}=\dfrac{4}{5}\)