So sánh:
a)\(12^{8} . 9^{12} với 18^{16}\)
b)\(\sqrt37 - \sqrt4 với 6 - \sqrt15 \)
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a/
\(2^{225}=\left(2^3\right)^{75}=8^{75}\)
\(3^{150}=\left(3^2\right)^{75}=9^{75}\)
\(8< 9\Rightarrow8^{75}< 9^{75}\Rightarrow2^{225}< 3^{150}\)
b/
\(12^8.9^{12}=\left(2^2\right)^8.3^8.\left(3^2\right)^{12}=2^{16}.3^{32}\)
\(18^{16}=2^{16}.\left(3^2\right)^{16}=2^{16}.3^{32}\)
\(\Rightarrow12^8.9^{12}=18^{16}\)
c/
\(45^{10}.5^{30}=\left(3^2\right)^{10}.5^{10}.5^{30}=3^{20}.5^{40}\)
\(75^{20}=3^{20}.\left(5^2\right)^{20}=3^{20}.5^{40}\)
\(\Rightarrow45^{10}.5^{30}=75^{20}\)
a) (-4). (-8) > 0
b) (-23). 6 < (-4). (-15)
c) (+12) .(+7) < (-9). (-10)
a) 1/2
b) 18/17; 17/16; 16/15; 15/14; 14/13; 13/12; 10/9
Nhớ k cho mk nha
a)1/2
b)Vì 18/17 <17/16 <16/15<15/14< 14/13< 13/12< 10/9
Nên, ta có:
18/17; 17/16; 16/15; 15/14; 14/13; 13/12; 10/9.
\(A=\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot8+9\cdot12+12\cdot16+15\cdot20}\)
\(=>A=\frac{1\cdot2+4\cdot1\cdot2+9\cdot1\cdot2+16\cdot1\cdot2+25\cdot1\cdot2}{3\cdot4+4\cdot3\cdot4+9\cdot3\cdot4+16\cdot3\cdot4+25\cdot3\cdot4}\)
\(=>A=\frac{\left(1+4+9+16+25\right)\cdot1\cdot2}{\left(1+4+9+16+25\right)\cdot3\cdot4}=\frac{1}{6}=\frac{111111}{666666}\)
Mà \(\frac{111111}{666666}< \frac{111111}{666665}\)
\(=>A< B\)
a: =6/12*7/14*8/16*9/18=1/2*1/2*1/2*1/2=1/16
b: =4/12*15/3*9/25*24/8
=1/3*3*5*9/25=9/5