\(\frac{2\times6^9-2^5\times18^4}{2^6\times6^8}\)
tính hợp lí
\(\frac{2\times6^9-2^5\times18^4}{2^6\times6^8}\)
tính hợp lí
\(\frac{4}{2\times4}+\frac{4}{4\times6}+\frac{4}{6\times8}+\frac{4}{8\times10}+...+\frac{4}{16\times18}+\frac{4}{18\times20}\)
Gọi tổng là A ta có:
\(A.2=\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{18.20}\)
\(A.2=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{18}-\frac{1}{20}\)
\(A.2=\frac{1}{2}-\frac{1}{20}\)
\(A=\frac{9}{20}:2=\frac{9}{40}\)
Tính hợp lí
H = \(\frac{2\times8^4+27^2+4\times6^9}{2^7\times6^7+2^7\times40\times9^4}\)
Tính nhanh:\(\frac{1\times2\times3+2\times4\times6+3\times6\times9+4\times8\times12+5\times10\times15}{1\times3\times5+2\times6\times10+3\times9\times15+4\times12\times20+5\times15\times25}-\frac{1+2+3+2+4+6+3+6+9+4+8+12+5+10+15}{1+3+5+2+6+10+3+9+15+4+12+20+5+15+25}\)
\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}\)
\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
\(=\frac{\left(2^2\right)^5.\left(3^2\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8+\left(2.3\right)^8.2^2.5}\)
\(=\frac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}\)
\(=\frac{2^{10}.3^8.\left(1-3\right)}{2^{10}.3^8.\left(1+5\right)}\)
\(=\frac{-1}{3}\)
Ta có:
\(\frac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)
\(=\frac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)
\(=\frac{2^{10}\cdot3^8\cdot\left(1-3\right)}{2^{10}\cdot3^8\cdot\left(1+5\right)}\)
\(=-\frac{2}{6}=-\frac{1}{3}\)
\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}\)
\(=\frac{2^{10}\times3^8-2^{10}.3^9}{2^{10}\times3^8+2^{10}\times3^8\times5}\)
\(=\frac{2^{10}\times3^8\left(1-3\right)}{2^{10}\times3^8\left(1+5\right)}\)
\(=\frac{-1}{3}\)
Tính :\(\frac{5^2\times6^{11}\times6^2\times12^6\times15^2}{2\times6^{12}\times10^4-81^2\times960^3}\)
CẦN GẤP !! TRÌNH BÀY ĐẦY ĐỦ !!!
\(\frac{9\times15\times21\times12\times20}{5\times6\times45\times18\times4}=?\)
=\(\frac{3\times3\times3\times5\times3\times7\times2\times6\times4\times5}{5\times2\times3\times5\times3\times3\times3\times6\times4}=7\)
\(\frac{9x15x21x12x20}{5x6x45x18x4}=\frac{3x3x15x3x7x3x4x5x4}{5x6x15x3x3x3x2x4}=\frac{15x7x3x4}{6x2}=\frac{1260}{12}=105\)
\(\orbr{\frac{2^{10}\times3^8+6^8\times20}{2\times6^9-4^5\times9^4}}\)
tính giá trị biểu thúc : \(\frac{1}{2}\times\frac{2\times6}{3\times6\times8}\times\frac{4\times6}{6\times2\times2}\times\frac{4\times5\times2}{2\times8\times10}\)
\(\frac{1.2.6.4.6.4.5.2}{2.3.6.8.6.2.2.2.8.10}=\frac{1}{96}\)
Gía trị của biểu thức là : \(\frac{1x2x3x2x2x2x2x3x2x2x2x5x2}{2x3x3x2x4x2x3x2x2x2x2x4x2x5x2}\)= \(\frac{1}{48}\)