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\(\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}=\frac{5^2.6^{11}.6^2.6^2.6^6.2^6.3^2.5^2}{2.2^{12}.3^{12}2^4.5^4-3^8.2^{15}.3^3}=\frac{5^6.6^{21}.2^8.3^2}{2^{17}.3^{12}.5^4-3^{11}.2^{15}}=\frac{5^6.3^{23}.2^{29}}{3^{11}.2^{15}.\left(2^2.3.5^4-1\right)}=\frac{5^6.3^{13}.2^{14}}{2^2.3.5^4-1}\)
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
làm cách trình bày ra nhé biết kết quả là \(\frac{388}{7199}\)
Đặt \(A=\frac{\left(5^2.6^{11}.16^2+6^2.12^6.15^2\right).10}{2.6^{12}.10^4-81^2.960^3}\)
\(A=\frac{\left(5^2.2^{11}.3^{11}.2^8+2^2.3^2.3^3.2^{12}.3^2.5^2\right).10}{2.2^{12}.3^{12}.2^4.5^4-9^4.2^{18}.3^3.5^3}\)
\(A=\frac{5^2.2^{11}.3^{11}.2^8.2.5+2^2.3^2.2^{12}.3^25^2.2.5}{2^{15}.\left(2^2.3^{12}.5^4-9^4.2^3.3^3.5^3\right)}\)
\(A=\frac{2^{15}\left(5^3.2^5.3^{11}+3^4.5^3\right)}{2^{15}.\left(2^2.3^{12}.5^4-9^4.2^3.3^3.5^3\right)}\)
\(A=\frac{5^3.2^5.3^{11}+3^4.5^3}{2^2.3^{12}.5^4-9^4.2^3.3^3.5^3}\)
\(A=\frac{5^3\left(2^5.3^{11}+3^4\right)}{5^3\left(2^2.3^{12}.5-9^4.2^3.3^3\right)}\)\(A=\frac{2^5.3^{11}+3^4}{2^2.3^{12}.5-9^4.2^3.3^3}\)
\(A=\frac{3^4.\left(2^5.3^8.5+1\right)}{3^4\left(2^2.3^8.5-3^4.2^3.3^3\right)}\)
\(A=\frac{2^5.3^8.5+1}{2^2.3^8.5-3^4.2^3.3^3}\)
Cậu phân tích từ từ
Ta có: \(\frac{5^2.6^{11}.16^2+6^2.12^6.15^2}{2.6^{12}.10^4-81^2.960^3}\)
\(=\frac{5^2.2^{11}.3^{11}.2^8+2^2.3^2.3^6.2^{12}.5^2.3^5}{2.2^{12}.3^{12}.2^4.5^4-3^8.2^{18}.3^3.5^3}\)
\(=\frac{5^2.2^{19}.3^{11}+3^{13}.2^{14}.5^2}{2^{17}.3^{12}.5^4-2^{18}.3^{11}.5^3}\)
\(=\frac{\left(5^2.2^{14}.3^{11}\right)\left(2^5+3^2\right)}{\left(2^{17}.3^{11}.5^3\right)\left(3.5-2\right)}\)
\(=\frac{\left(2^5+3^2\right)}{\left(2^3.5\right)\left(3.5-2\right)}\)
\(=\frac{32+9}{40.13}\)
\(=\frac{41}{520}\)