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\(a)\left(-2.x^2.y\right).\left(5.x.y^4\right)\)
\(=\left(-2.5\right)\left(x^2.x\right)\left(y.y^4\right)\)
\(=-10.x^3.y^5\)
Bậc : \(3+5=8\)
Hệ số : \(-10\)
\(b)\left(\frac{27}{10}.x^4.y^2\right).\left(\frac{5}{9}.x.y\right)^0\)
\(=\frac{27}{10}.x^4.y^2.1\)
\(=\frac{27}{10}.x^4.y^2\)
Bậc : \(4+2=6\)
Hệ số : \(\frac{27}{10}\)
\(c)\left(\frac{1}{3}.x^3.y\right).\left(-xy\right)^2\)
\(=\frac{1}{3}.x^3y.\left(-x\right)^2.y^2\)
\(=\frac{1}{3}.x^3.y.x^2.y^2\)
\(=\frac{1}{3}.\left(x^3.x^2\right).\left(y.y^2\right)\)
\(=\frac{1}{3}x^5.y^3\)
Bậc : \(5+3=8\)
Hệ số : \(\frac{1}{3}\)
Chúc bạn học tốt !!!
a) ta có: \(\left(\frac{1}{3}\right)^{20}=\left[\left(\frac{1}{3}\right)^4\right]^5=\left(\frac{1}{81}\right)^5< \left(\frac{1}{80}\right)^5\)
b) ta có: 231 = 230.2 = (23)10.2 = 810.2
321 = 320.3 = (32)10.3 = 910.3
=> 8^10.2 < 9^10,3
=> 2^31 < 3^21
\(a,\left(\frac{1}{80}\right)^5>\left(\frac{1}{81}\right)^5=\left(\frac{1}{3}\right)^{20}\)
\(b,2^{31}=2.2^{30}=2.8^{10}< 3.8^{10}< 3.9^{10}=3^{21}\)
\(\frac{4}{5}:1\frac{2}{5}=2\frac{2}{5}:x\)
\(=\frac{4}{7}=2\frac{2}{5}:x\)
\(\Rightarrow x=2\frac{2}{5}:\frac{4}{7}=\frac{21}{5}\)
\(\Rightarrow x=\frac{21}{5}\)
Ủng hộ mk nka!^_^
a) \(\frac{x+2015}{5}+\frac{x+2015}{6}=\frac{x+2015}{7}+\frac{x+2015}{8}\)
\(\frac{x+2015}{5}+\frac{x+2015}{6}-\frac{x+2015}{7}-\frac{x+2015}{8}=0\)
\(\left(x+2015\right).\left(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}-\frac{1}{8}\right)=0\)
vì \(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}-\frac{1}{8}\ne0\)
\(\Rightarrow\)x + 2015 = 0
\(\Rightarrow\)x = -2015
b) Tương tự
-0.7<\(\dfrac{-1}{3}\)
\(\dfrac{-1}{5}< \dfrac{2}{5}\)
-0.75 < -0.1
\(\dfrac{5}{4}>\dfrac{4}{5}\)