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-8/27 = (-2/3)3 nha còn cái kia mình cụng ko bít đâu mình cũng đang hỏi
\(\dfrac{81}{125}=\dfrac{3^4}{5^3}\) ; \(-\dfrac{8}{27}=-\left(\dfrac{2}{3}\right)^3\)
\(\dfrac{81}{125}=\dfrac{3^4}{5^3}\)
\(\dfrac{-8}{27}=\dfrac{\left(-2\right)^3}{3^3}=\left(\dfrac{-2}{3}\right)^3\)
Ta có:
\(\dfrac{81}{125}=\dfrac{3^4}{5^4}=\left(\dfrac{3}{5}\right)^4\)
\(-\dfrac{8}{27}=-\dfrac{2^3}{3^3}=\left(-\dfrac{2}{3}\right)^3\)
d)\(-\frac{8}{27}=\frac{\left(-2\right)^3}{3^3}=\left(-\frac{2}{3}\right)^3\)
h)\(-\frac{27}{64}=\frac{\left(-3\right)^3}{4^3}=\left(-\frac{3}{4}\right)^3\)
\(\frac{-8}{27}=\frac{\left(-2\right)^3}{3^3}\)
\(\frac{-27}{64}=\frac{-3^3}{4^3}\)
Bài 3:
a) \(\left(x-\frac{1}{2}\right)^2=0\)
\(\Rightarrow x-\frac{1}{2}=0\)
\(\Rightarrow x=\frac{1}{2}\)
Vậy \(x=\frac{1}{2}\)
b) \(\left(x-2\right)^2=1\)
\(\Rightarrow x-2=\pm1\)
+) \(x-2=1\Rightarrow x=3\)
+) \(x-2=-1\Rightarrow x=1\)
Vậy \(x=3\) hoặc \(x=1\)
c) \(\left(2x-1\right)^3=-8\)
\(\Rightarrow\left(2x-1\right)^3=\left(-2\right)^3\)
\(\Rightarrow2x-1=-2\)
\(\Rightarrow2x=-1\)
\(\Rightarrow x=\frac{-1}{2}\)
Vạy \(x=\frac{-1}{2}\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
\(\Rightarrow\left(x+\frac{1}{2}\right)^2=\left(\frac{1}{4}\right)^2\)
\(\Rightarrow x+\frac{1}{2}=\frac{1}{4}\)
\(\Rightarrow x=\frac{-1}{4}\)
Vậy \(x=\frac{-1}{4}\)
\(2^6\)\(0,5^2\)\(\left(\frac{1}{2}\right)^4\)\(\left(\frac{1}{2}\right)^8\)\(\left(\frac{11}{12}\right)^2\)
\(125=5^3\)
\(-125=\left(-5\right)^3\)
\(27=3^3\)
\(-27=\left(-3\right)^3\)
^...^ 
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Bài 11: Viết các số sau dưới dạng lũy thừa với số mũ khác 1:
125 = 53
(-125) = (-5)3
27 = 33
(-27) = (-3)3
\(\frac{8^{11}.3^{17}}{27^{10}.9^{15}}=\frac{8^{11}.3^{17}}{3^{30}.3^{30}}=\frac{8^{11}}{3^{13}.3^{30}}=\frac{8^{11}}{3^{43}}\)
\(\frac{\left(5^4-5^3\right)^3}{125^4}=\frac{[\left(5-1\right).5^3]^3}{5^{12}}=\frac{\left(4.5^3\right)^3}{5^{12}}=\frac{64.5^9}{5^{12}}=\frac{64}{5^3}=\left(\frac{4}{5}\right)^3\)
\(\frac{4^{20}-2^{20}+6^{20}}{6^{20}-3^{20}+9^{20}}=\frac{2^{40}-2^{20}+6^{20}}{6^{20}-3^{20}+3^{40}}=\frac{2^{20}.\left(2^{20}-1+3^{30}\right)}{3^{20}.\left(2^{20}-2+3^{20}\right)}=\frac{2^{20}}{3^{20}}=\left(\frac{2}{3}\right)^{20}\)
\(\dfrac{81}{125}-\dfrac{8}{27}=\dfrac{3^4}{5^3}-\dfrac{2^3}{3^3}\)
\(\frac{9^2}{5^3}\)- \(\frac{2^3}{3^3}\)