Rút gọn
\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}\)
\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}\)
\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
\(=\frac{\left(2^2\right)^5.\left(3^2\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8+\left(2.3\right)^8.2^2.5}\)
\(=\frac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}\)
\(=\frac{2^{10}.3^8.\left(1-3\right)}{2^{10}.3^8.\left(1+5\right)}\)
\(=\frac{-1}{3}\)
Ta có:
\(\frac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)
\(=\frac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)
\(=\frac{2^{10}\cdot3^8\cdot\left(1-3\right)}{2^{10}\cdot3^8\cdot\left(1+5\right)}\)
\(=-\frac{2}{6}=-\frac{1}{3}\)
\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}\)
\(=\frac{2^{10}\times3^8-2^{10}.3^9}{2^{10}\times3^8+2^{10}\times3^8\times5}\)
\(=\frac{2^{10}\times3^8\left(1-3\right)}{2^{10}\times3^8\left(1+5\right)}\)
\(=\frac{-1}{3}\)
\(\orbr{\frac{2^{10}\times3^8+6^8\times20}{2\times6^9-4^5\times9^4}}\)
Tính nhanh:\(\frac{1\times2\times3+2\times4\times6+3\times6\times9+4\times8\times12+5\times10\times15}{1\times3\times5+2\times6\times10+3\times9\times15+4\times12\times20+5\times15\times25}-\frac{1+2+3+2+4+6+3+6+9+4+8+12+5+10+15}{1+3+5+2+6+10+3+9+15+4+12+20+5+15+25}\)
Các bạn ơi ,giúp mình với
Bài 1:Rút gọn
a)\(\frac{2^{19}\times27^3+15\times4^9\times9^4}{6^9\times2^{10}+12^{10}}\)
b)\(\frac{\left(\frac{-1}{2}\right)^3-\left(\frac{3}{4}\right)^3\times\left(-2\right)^2}{2\times\left(-1\right)^5+\left(\frac{3}{4}\right)^2-\frac{3}{8}}\)
c)\(\frac{45\times9^4-2\times6^4}{2^{19}\times3^8+6^8\times20}\)
Bài 2:Tìm x
a)\(5^x+5^{x+2}=650\)
b)\(3^{x-1}+5\times3=162\)
Tính nhanh: \(E=\frac{4^9\times9^5+6^9\times2^6}{2^{10}\times3^8+6^8\times20}\)
\(E=\frac{4^9.9^5+6^9.2^6}{2^{10}.3^8+6^8.20}=\frac{\left(2^2\right)^9.\left(3^2\right)^5+6^9.64}{2^{10}.3^8+6^8.20}=\frac{2^{18}.3^{10}+6^9.64}{2^{10}.3^8+6^8.20}=\frac{2^8.3^2+6.2^4}{1.1+1.5}=\frac{2304+96}{6}=\frac{2400}{6}=400\)
M=\(\frac{9^4\times27^5\times3^6\times3^4}{3^8\times81^4\times243\times8^2}\)
N=4\(\frac{4^6\times9^5\times6^9\times120}{8^4\times3^{12}-6^{11}}\)
tính \(\frac{4^6\times9^5+120\times6^9}{8^4\times3^{12}-6^{11}}\)
Bài làm :
\(\frac{4^6\times9^5+120\times6^9}{8^4\times3^{12}-6^{11}}\)
\(=\frac{\left(2^2\right)^6\times\left(3^2\right)^5+2^3\times5\times3\times\left(2\times3\right)^9}{\left(2^3\right)^4\times3^{12}-\left(2\times3\right)^{11}}\)
\(=\frac{2^{12}\times3^{10}+2^3\times5\times3\times2^9\times3^9}{2^{12}\times3^{12}-2^{11}\times3^{11}}\)
\(=\frac{2^{12}\times3^{10}\times\left(1+5\right)}{2^{11}\times3^{11}\times\left(2\times3-1\right)}\)
\(=\frac{2\times6}{3\times5}\)
\(=\frac{4}{5}\)
Học tốt nhé
tính :\(\frac{1}{1\times2\times3}+\frac{1}{2\times3\times4}+\frac{1}{3\times4\times5}+\frac{1}{4\times5\times6}+\frac{1}{5\times6\times7}+\frac{1}{6\times7\times8}+\frac{1}{7\times8\times9}+\frac{1}{8\times9\times10}\)
\(\frac{1}{1.2.3}+\frac{1}{2.3.4}+...+\frac{1}{8.9.10}=\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{2.3}\right)+\frac{1}{2}.\left(\frac{1}{2.3}-\frac{1}{3.4}\right)+...+\frac{1}{2}.\left(\frac{1}{8.9}-\frac{1}{9.10}\right)\)
\(=\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{8.9}-\frac{1}{9.10}\right)\)
\(\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{9.10}\right)=\frac{1}{2}.\frac{22}{45}=\frac{11}{45}\)
\(\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}+\frac{1}{6\times7}+\frac{1}{7\times8}+\frac{1}{8\times9}+\frac{1}{9\times10}\)
1/2.3+1/3.4+1/4.5+1/5.6+1/6.7+1/7.8+1/8.9+1/9.10
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6+1/7-1/7+1/8-1/8+1/9+1/9-1/10
=1/2-1/10
=5/10-1/10
=4/10=2/5
\(\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}+\frac{1}{5x6}+\frac{1}{6x7}+\frac{1}{8x9}+\frac{1}{9x10}\)
\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\)
\(\frac{1}{2}-\frac{1}{10}\)
\(\frac{2}{5}\)
= 1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
= 1/2-0-0-0-0-0-0-0-0-1/10
=1/2 - 1/10
=2/5
tớ trước nhé