Rút gọn biểu thức theo cách hợp lí:
P=\(\frac{2^{12}\cdot3^5-4^6\cdot3^6}{2^{12}\cdot9^3+8^4-3^5}\)
Rút gọn :
P=\(\frac{2^{12}\cdot3^5-4^6\cdot3^6}{2^{12}\cdot9^3-8^4\cdot3^5}\)
RÚT GỌN
a/\(\frac{9^4\cdot27^5\cdot3^6\cdot3^4}{3^8\cdot81^4\cdot234\cdot8^6}\)
b/\(N=\frac{4^6\cdot9^5+6^6\cdot120}{8^4-3^{12}-6}\)
\(\frac{2^{12}\cdot3^5-4^6\cdot3^6}{2^{12}\cdot9^3+8^4\cdot3^3}\)
\(\frac{2^{12}.3^5-\left(2^2\right)^6.3^6}{2^{12}.\left(3^2\right)^3+\left(2^3\right)^4.3^3}\)
\(\frac{2^{12}.3^5.\left(1-3^{ }\right)}{2^{12}.3^3.\left(3^3-1\right)}\)
\(\frac{2^{12}.3^5.\left(-2\right)}{2^{12}.3^3.8}\)
\(\frac{3^2.\left(-1\right)}{4}\)
\(\frac{-9}{4}\)
VẬy.......................
nhớ tk cho mình nha
1.Rút gọn(nếu cần) rồi so sánh
\(\frac{\left(-5\right)^2-5\cdot3^2}{5^3+5^2\cdot3^2}\) ;\(\frac{4^6\cdot9^5+6^9\cdot120}{8^4\cdot3^{12}-6^{11}}\) và\(\frac{2929-101}{2\cdot1919+404}\)
\(TínhA=\frac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}-\frac{5^{10}\cdot7^3-25^5\cdot49^2}{\left(125\cdot7\right)^3+5^9\cdot14^3}\)
\(B=\frac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}-\frac{56^{10}\cdot7^3-25^5\cdot49^2}{\left(125\cdot7\right)^3+5^9\cdot14^3}\)
Bài 1 Cho biểu thức
P= \(\frac{6n+5}{2n-4}\)
a) Với giá trị nào của n thì P là phân số
b) Tìm n thuộc Z để P thuộc Z
c) Tính P khi |2n-3|=\(\frac{5}{3}\)
Bài 2 Rút gọn phân số
a) M= \(\frac{9^4\cdot27^5\cdot3^6\cdot3^4}{3^8\cdot81^4\cdot23^4\cdot8^2}\)
b) N= \(\frac{4^6\cdot9^5+6^9\cdot120}{8^4\cdot3^{12}-6^{11}}\)
Ta có :
\(M=\frac{9^4.27^5.3^6.3^4}{3^8.81^4.23^4.8^2}\)
\(M=\frac{\left(3^2\right)^4.\left(3^3\right)^5.3^{10}}{3^8.\left(3^4\right)^4.23^4.8^2}\)
\(M=\frac{3^8.3^{15}.3^{10}}{3^8.3^{16}.23^4.8^2}\)
\(M=\frac{3^{33}}{3^{24}.23^4.8^2}\)
\(M=\frac{3^9}{23^4.8^2}\)
Bài 1
a) \(P=\frac{6n+5}{2n-4}=\frac{6n-12+7}{2n-4}=3+\frac{7}{2n-4}\)
Để P là phân số thì \(\hept{\begin{cases}2n-4\ne7\\2n-4\ne1\end{cases}}\Leftrightarrow\hept{\begin{cases}n\ne\frac{11}{2}\\n\ne\frac{5}{2}\end{cases}}\)
Vậy...
b) \(P=\frac{6n+5}{2n-4}=3+\frac{7}{2n-4}\)
Để \(P\in Z\)thì \(\orbr{\begin{cases}2n-4=7\\2n-4=1\end{cases}\Leftrightarrow\orbr{\begin{cases}n=\frac{11}{2}\notin Z\\n=\frac{5}{2}\notin Z\end{cases}}}\)
Vậy không có giá trị n nào thuộc Z để P thuộc Z.
c) \(\left|2n-3\right|=\frac{5}{3}\)
Trường hợp: \(2n-3=\frac{5}{3}\Rightarrow n=\frac{7}{3}\)
\(P=\frac{6.\frac{7}{3}+5}{2.\frac{7}{3}-4}=\frac{19}{\frac{2}{3}}=\frac{57}{2}\)
Trường hợp: \(2n-3=-\frac{5}{3}\Rightarrow n=\frac{2}{3}\)
\(P=\frac{6.\frac{2}{3}+5}{2.\frac{2}{3}-4}=\frac{9}{\frac{-8}{3}}=\frac{27}{-8}\)
Bài 2
\(N=\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\frac{\left(2^2\right)^6.\left(3^2\right)^5+\left(2.3\right)^{10}.4.5}{\left(2^3\right)^4.3^{12}-\left(2.3\right)^{11}}\)
\(=\frac{2^{12}.3^{10}+5.2^{12}.3^{10}}{2^{12}.3^{12}-6^{11}}=\frac{6.2^{12}.3^{10}}{6^{12}-6^{11}}\)
\(=\frac{2.3.2^{12}.3^{10}}{6.6^{11}-6^{11}}=\frac{2^{13}.3^{11}}{5.\left(2.3\right)^{11}}=\frac{2^{13}.3^{11}}{5.2^{11}.3^{11}}=\frac{4}{5}\)
Tính A:\(\frac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}-\frac{5^{10}\cdot7^3-25^5\cdot49^2}{\left(125\cdot7\right)^3+5^9\cdot14^3}\)
thực hiện phép tính:
A = \(\frac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}-\frac{5^{10}\cdot7^3-25^5\cdot49}{\left(125\cdot7\right)^3+5^9\cdot14^3}^2\)
Thực hiện phép tính
\(\dfrac{2^{12}\cdot3^5-4^6\cdot3^6}{2^{12}\cdot9^3+8^4\cdot3^5}\)
\(\dfrac{2^{12}.3^5-4^6.3^6}{2^{12}.9^3+8^4.3^5}=\dfrac{2^{12}.3^5-\left(2^2\right)^6.3^6.3}{2^{12}.\left(3^2\right)^3+\left(2^3\right)^4.3^5}.\)
\(=\dfrac{2^{12}.3^5-2^{12}.3^6}{2^{12}.3^6+2^{12}.3^5}=\dfrac{2^{12}\left(3^5-3^6\right)}{2^{12}\left(3^5+3^6\right)}=\dfrac{3^5-3^6}{3^5+3^6}=-\dfrac{486}{972}=-\dfrac{1}{2}.\)
Vậy..........