Ta có:

\(0,032ha=0,032\times10000=320m^2\)

Vì: \(320m^2< 3200m^2\) nên \(0,032ha< 3200m^2\)

Vậy: \(0,032ha< 3200m^2\)

\(\dfrac{6x}{15y^3}\cdot\dfrac{10y^3}{x^2}=\dfrac{6x\cdot10y^3}{15y^3\cdot x^2}=\dfrac{2\cdot3\cdot x\cdot5y^3\cdot2}{5y^3\cdot3\cdot x\cdot x}=\dfrac{4}{x}\)

\(b,\left(\dfrac{a}{a^2}-\dfrac{1}{a}\right):\left(\dfrac{1}{b}+\dfrac{1}{a}\right)\\ =\left(\dfrac{1}{a}-\dfrac{1}{a}\right):\left(\dfrac{1}{b}+\dfrac{1}{a}\right)\\ =0:\left(\dfrac{1}{b}+\dfrac{1}{a}\right)\\ =0\)

\(\rightarrow A.\) Triều Tiên.

\(+\) Trung Quốc và Triều Tiên có chung đường biên giới trên đất liền dài khoảng \(1416km\)

\(9673=9\cdot10^3+6\cdot10^2+7\cdot10^1+3\cdot10^0\)

\(3547=3\cdot10^3+5\cdot10^2+4\cdot10^1+7\cdot10^0\)

\(abcde=a\cdot10^4+b\cdot10^3+c\cdot10^2+d\cdot10^1+e\cdot10^0\)

\(\left(7x-11\right)^3=2^5\cdot5^2+200\\ \Rightarrow\left(7x-11\right)^3=32\cdot25+200\\ \Rightarrow\left(7x-11\right)^3=800+200\\ \Rightarrow\left(7x-11\right)^3=1000\\ \Rightarrow\left(7x-11\right)^3=10^3\\ \Rightarrow7x-11=10\\ \Rightarrow7x=10+11\\ \Rightarrow7x=21\\ \Rightarrow x=21:7\\ \Rightarrow x=3\)

\(0,27\times4500+1,35\times550\times2\\ =0,27\times10\times450+\left(1,35\times2\right)\times550\\ =2,7\times450+2,7\times550\\ =2,7\times\left(450+550\right)\\ =2,7\times1000\\ =2700\)

\(\left(7,5\times18,3+26,4\times28,3\right)\times\left(47\times11-4700\times0,1-47\right)\\ =\left(7,5\times18,3+26,4\times28,3\right)\times\left(517-470-47\right)\\ =\left(7,5\times18,3+26,4\times28,3\right)\times0\\ =0\)

\(648-123-377+202-148\\ =\left(648-148\right)-\left(123+377\right)+202\\ =500-500+202\\ =0+202\\ =202\)

\(\left(2^8+8^3\right):\left(2^5\cdot2^3\right)\\ =\left[2^8+\left(2^3\right)^3\right]:2^{5+3}\\ =\left(2^8+2^9\right):2^8\\ =2^8:2^8+2^9:2^8\\ =1+2\\ =3\)