rút gọn :
a,\(\frac{790^4}{79^4}\)
b, \(\frac{15^{30}}{45^{13}}\)
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
NT
2
PA
13 tháng 10 2016
\(\frac{3^6\times45^4-15^{13}\times5^{-9}}{27^4\times25^3+45^6}\)
\(=\frac{3^6\times\left(3^2\times5\right)^4-\left(3\times5\right)^{13}\times5^{-9}}{\left(3^3\right)^4\times\left(5^2\right)^3+\left(3^2\times5\right)^6}\)
\(=\frac{3^6\times3^8\times5^4-3^{13}\times5^{13}\times5^{-9}}{3^{12}\times5^6+3^{12}\times5^6}\)
\(=\frac{3^{14}\times5^4-3^{13}\times5^4}{3^{12}\times5^6+3^{12}\times5^6}\)
\(=\frac{3^{13}\times5^4\times\left(3-1\right)}{2\times3^{12}\times5^6}\)
\(=\frac{3\times2}{2\times5^2}\)
\(=\frac{3}{25}\)
LL
1
M
11 tháng 2 2018
a) \(\frac{2}{5}+\frac{9}{15}=\frac{2}{5}+\frac{3}{5}=\frac{5}{5}=1\)
b) \(\frac{15}{45}+\frac{25}{30}=\frac{1}{3}+\frac{5}{6}=\frac{2}{6}+\frac{5}{6}=\frac{7}{6}\)
c) \(\frac{28}{32}+\frac{45}{72}=\frac{7}{8}+\frac{5}{8}=\frac{12}{8}=\frac{3}{2}\)
d) \(\frac{8}{28}+\frac{5}{30}=\frac{2}{7}+\frac{1}{6}=\frac{12}{42}+\frac{7}{42}=\frac{19}{42}\)
11 tháng 2 2018
a) \(\frac{2}{5}+\frac{9}{15}\)=\(\frac{2}{5}+\frac{3}{5}=\frac{2+3}{5}=1\)
b)\(\frac{15}{45}+\frac{25}{30}=\frac{1}{3}+\frac{5}{6}=\frac{2}{6}+\frac{5}{6}=\frac{2+5}{6}=\frac{7}{6}\)
c)\(\frac{28}{32}+\frac{45}{72}=\frac{7}{8}+\frac{5}{8}=\frac{7+5}{8}=\frac{12}{8}=\frac{3}{2}\)
d)\(\frac{8}{28}+\frac{5}{30}=\frac{2}{7}+\frac{1}{6}=\frac{12}{42}+\frac{7}{42}=\frac{12+7}{42}=\frac{19}{42}\)
F
1
19 tháng 2 2017
1.
a) \(\frac{16}{24}-\frac{1}{3}=\frac{16}{24}-\frac{8}{24}=\)\(\frac{8}{24}=\frac{1}{3}\)
b) \(\frac{4}{5}-\frac{12}{60}=\frac{48}{60}-\frac{12}{60}=\frac{36}{60}=\frac{9}{15}\)
3.
a)\(\frac{17}{6}-\frac{2}{6}=\frac{17-2}{6}=\frac{15}{6}\)
b) \(\frac{16}{15}-\frac{11}{15}=\frac{16-11}{15}=\frac{5}{15}=\frac{1}{3}\)
c) \(\frac{19}{12}-\frac{13}{12}=\frac{19-13}{12}=\frac{6}{12}=\frac{1}{2}\)
VN
24 tháng 1 2017
a)
\(=-\frac{1}{2187}.2187\)
\(=-1\)
b)
\(=\frac{1}{512}.512\)
\(=1\)
c)
\(=\frac{8100}{225}=36\)
d) \(=10000\)
2 tháng 10 2016
b/ \(\frac{2\sqrt{2}-1}{\sqrt{2}-1}+\frac{3\sqrt{2}-2}{\sqrt{2}-3}=\frac{\left(2\sqrt{2}-1\right)\left(\sqrt{2}+1\right)}{1}+\frac{\left(2-3\sqrt{2}\right)\left(3+\sqrt{2}\right)}{\left(3-\sqrt{2}\right)\left(3+\sqrt{2}\right)}\)
\(=3+\sqrt{2}+\frac{-7\sqrt{2}}{7}=3\)
c/ \(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}=\sqrt{13+30\sqrt{2+\sqrt{\left(2\sqrt{2}+1\right)^2}}}\)
\(=\sqrt{13+30\sqrt{\left(\sqrt{2}+1\right)^2}}=\sqrt{43+30\sqrt{2}}=\sqrt{\left(5+3\sqrt{2}\right)^2}=5+3\sqrt{2}\)
1 tháng 10 2016
Mình đưa ra đáp án thôi nhé :)
a/ \(\left(\sqrt{\frac{5}{3}-\sqrt{\frac{3}{5}}}\right).\sqrt{15}=\sqrt{25-3\sqrt{15}}\)
b/ \(\frac{2\sqrt{2}-1}{\sqrt{2}-1}+\frac{3\sqrt{2}-2}{\sqrt{2}-3}=3\)
c/ \(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}=5+3\sqrt{2}\)
a) \(\frac{790^4}{79^4}\)
\(=\frac{\left(79.10\right)^4}{79^4}\)
\(=\frac{79^4.10^4}{79^4}\)
\(=10^4\)
\(=10000\)
790^4/79^4
= (79.10)^4/79^4
= 79^4.10^4/79^4
= 10^4