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đây nhé
a)\(\dfrac{2^{15}.3^8}{2^6.3^6.2^9}\)\(\dfrac{ }{ }\)=\(^{3^2}\)=9
b)\(\dfrac{2^{12}.3^{10}+2^9.3^9.2^3.15}{-2^{12}.3^{12}-2^{11}.3^{11}}\)=\(\dfrac{2^{11}.3^{11}.\left(1+15\right)}{2^{11}.3^{11}\left(-2.3-1\right)}\)
=\(\dfrac{32}{-21}\)
c)\(\dfrac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}\)=\(\dfrac{2^{10}.3^8\left(1-3\right)}{2^{10}.3^8\left(1+5\right)}\)=\(-\dfrac{1}{3}\)
em dựa vào vd \(\dfrac{4^{16}}{2^8}\)= \(\dfrac{\left(2^2\right)^{16}}{2^8}=\dfrac{2^{16\cdot2}}{2^8}=2^4=16\)
1. sai dấu nhé
2.a, \(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(5^2.3\right)^{15}}=\frac{3^{20}.5^{30}}{5^{30}.3^{15}}=3^5=243\)
b, \(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(\frac{4}{5}\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\cdot2\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\right)^5\cdot2^5}{\left(\frac{2}{5}\right)^5\cdot\frac{2}{5}}=2^5\div\frac{2}{5}=32\cdot\frac{5}{2}=80\)
c, \(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^2}{2^{15}}=3^2=9\)
a.
\(\frac{45^{10}\times5^{20}}{75^{15}}=\frac{\left(3^2\times5\right)^{10}\times5^{20}}{\left(3\times5^2\right)^{15}}=\frac{3^{20}\times5^{10}\times5^{20}}{3^{15}\times5^{30}}=3^5=243\)
b.
\(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(0,8\right)^5}{\left(0,4\right)^5}\times\frac{1}{\left(0,4\right)}=\left(\frac{0,8}{0,4}\right)^5\times\frac{1}{\frac{4}{10}}=2^5\times\frac{5}{2}=2^4\times5=16\times5=80\)
c.
\(\frac{2^{15}\times9^4}{6^6\times8^3}=\frac{2^{15}\times\left(3^2\right)^4}{\left(2\times3\right)^6\times\left(2^3\right)^3}=\frac{2^{15}\times3^8}{2^6\times3^6\times2^9}=3^2=9\)
Chúc bạn học tốt ^^
Để A đạt GTLN thì \(\frac{3}{4-x}\)phải đạt giá trị lớn nhất\(\Rightarrow\)4-x phải bé nhất và 4-x>0
\(\Rightarrow4-x=1\rightarrow x=3\)
thay vào ta đc A=3
B3
\(B=\frac{7-x}{4-x}=\frac{4-x+3}{4-x}=\frac{4-x}{4-x}+\frac{3}{4-x}\)\(=1+\frac{3}{4-x}\)
Để b đạt GTLn thì 3/4-x phải lớn nhất (làm tương tụ như bài 2 )
Vậy gtln của 3/4-x là 3 thay vào ta đc b=4
Lâm như bài 2 Gtln của\(\frac{3}{4-x}\)
B1\(\frac{4x-3}{2x+1}=\frac{4x+2-5}{2x+1}=\frac{2.\left(2x+1\right)-5}{2x+1}\)\(=\frac{2.\left(2x+1\right)}{2x+1}-\frac{5}{2x+1}=2-\frac{5}{2x+1}\)
VÌ A\(\varepsilon Z\),2\(\varepsilon Z\)\(\Rightarrow\)\(\frac{5}{2x+1}\varepsilon Z\)\(\rightarrow2x+1\varepsilonƯ\left(5\right)\)={1;-1;5;-5}
\(\Rightarrow\)x={0;-1;23}
1.Tính
(0,25)4.1024=(1/4)4.1024=4
2.So sánh
291=(213)7=81927
535=(55)7=31257
Mà 8192>3125=> 81927>31257
=> 291>535
3. Tìm giá trị biểu thức
a) \(\dfrac{45^{10^{ }}.5^{20^{ }}}{75^{15}}=\dfrac{\left(3^{2^{ }}.5\right)^{10^{ }}.5^{20}}{^{ }\left(3.5^2\right)^{15}}=\dfrac{3^{20}.5^{30}}{3^{15}.5^{30}}=3^5=243\)
b)\(\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}=\dfrac{\left(2.0,4\right)^5}{0,4.0,4^5}=\dfrac{2^{5^{ }}.0,4^5}{0,4.0,4^5}=\dfrac{2^5}{0,4}=80\)
c)\(\dfrac{2^{15}.9^4}{6^6.8^3}=\dfrac{2^{15^{ }}.3^8}{3^6.2^6.2^9}=\dfrac{2^{15}.3^8}{3^6.2^{15}}=3^2=9\)
Tic hộ tui đi !!! chúc bn hok tôts 
a) A = \(\frac{45^{10}.5^{10}}{75^{10}}=\frac{\left(5.3^2\right)^{10}.5^{10}}{\left(5^2.3\right)^{10}}=\frac{5^{10}.3^{20}.5^{10}}{5^{20}.3^{10}}=\frac{5^{20}.3^{10}}{5^{20}}=3^{10}=59049\)
b) B = \(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(0,2.2^2\right)^5}{\left(0,2.2\right)^6}=\frac{\left(0,2\right)^5.2^{10}}{\left(0,2\right)^6.2^6}=\frac{2^4}{0,2}=\frac{16}{0,2}=80\)
c) C = \(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.\left(3^2\right)^4}{\left(2.3\right)^6.\left(2^3\right)^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^2}{2^{15}}=3^2=9\)
\(A=\frac{\left(9^{10}×5^{10}×5^{10}\right)}{\left(25^{10}×3^{10}\right)}\)
\(A=\frac{\left(3^{20}×5^{20}\right)}{\left(5^{20}×3^{10}\right)}\)
\(A=\frac{3^{20}}{3^{10}}\)
\(A=3^{10}\)
I don't now
sorry
...................
nha
\(A=\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^2}{3^{15}}=9\)
\(B=\frac{45^{10}.5^{10}}{75^{10}}=\frac{5^{10}.3^{20}.5^{10}}{5^{20}.3^{10}}=3^{10}\)
\(C=\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(0,4\right)^5.\left(0,2\right)^5}{0,4^6}=\frac{0,2^5}{0,2^2}=0,2^3\)
\(D=\frac{8^{10}+4^{10}}{8^{11}+4^{11}}=\frac{4^{10}\left(2^{10}+1\right)}{4^{11}\left(2^{11}+1\right)}=\frac{2^{10}+1}{2^{13}+1}\)
\(\dfrac{2^{15}.9^4}{6^6.8^3}=\dfrac{2^{15}.3^8}{2^6.3^6.2^9}=\dfrac{2^{15}.3^8}{2^{15}.3^6}=3^2=9\)
Thanks nha