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C = 1930+5/1931+5
=>19C = 1931+95/1931+5 = 1+ [90/1931+5]
D = 1931+5/1932+5
=>19D = 1932+95/1932+5 = 1 + [90/1932+5]
ma 90/1931+5 > 90/1932+5
=>19C > 19D
=>C > D
a, Ta có:
3200 = ( 32) 100 = 9100
2300 = (23)100 = 8100
Nhận xét: 9100 > 8100
=) 3200 > 2300
b,
Ta có:
1255 = (53)5 = 515
257 = (52)7 = 514
Nhận xét: 515 > 514
=) 1255 > 257
a/ \(9^{27}=\left(3^2\right)^{27}=3^{54}\) và \(81^{13}=\left(3^4\right)^{13}=3^{52}\Rightarrow3^{54}>3^{52}\Rightarrow9^{27}>81^{13}\)
b/ \(5^{14}=\left(5^2\right)^7=25^7< 27^7\)
d/ \(2^{300}=\left(2^3\right)^{100}=8^{100}\) và \(3^{200}=\left(3^2\right)^{100}=9^{100}\Rightarrow8^{100}< 9^{100}\Rightarrow2^{300}< 3^{200}\)
f/ \(3^{450}=\left(3^3\right)^{150}=27^{150}\) và \(5^{300}=\left(5^2\right)^{150}=25^{150}\Rightarrow27^{150}>25^{150}\Rightarrow3^{450}>5^{300}\)
c/ \(10^{30}=\left(10^3\right)^{10}=1000^{10}\) và \(2^{100}=\left(2^{10}\right)^{10}=1024^{10}\Rightarrow1000^{10}< 1024^{10}\Rightarrow10^{30}< 2^{100}\)
đăng từng bài thui bạn êi ~.~
\(a)\)\(4x^3+12=120\)
\(\Leftrightarrow\)\(4x^3=108\)
\(\Leftrightarrow\)\(x^3=27\)
\(\Leftrightarrow\)\(x^3=3^3\)
\(\Leftrightarrow\)\(x=3\)
Vậy \(x=3\)
\(b)\) \(\left(4x-1\right)^2=25.9\)
\(\Leftrightarrow\)\(\left(4x-1\right)^2=5^2.3^2\)
\(\Leftrightarrow\)\(\left(4x-1\right)^2=\left(5.3\right)^2\)
\(\Leftrightarrow\)\(\left(4x-1\right)^2=15^2\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}4x-1=15\\4x-1=-15\end{cases}\Leftrightarrow\orbr{\begin{cases}4x=16\\4x=-14\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x=\frac{16}{4}\\x=\frac{-14}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=\frac{-7}{2}\end{cases}}}\)
Vậy \(x=4\) hoặc \(x=\frac{-7}{2}\)
Chúc bạn học tốt ~
\(\left(2x-15\right)^{15}=\left(2x-15\right)^3\)
\(\Leftrightarrow\)\(\left(2x-15\right)^{15}-\left(2x-15\right)^3=0\)
\(\Leftrightarrow\)\(\left(2x-15\right)^3[\left(2x-15\right)^{12}-1]=0\)
\(\Leftrightarrow\)\(\left(2x-15\right)^3=0\)
Hoặc \(\left(2x-15\right)^{12}-1=0\)
\(\Leftrightarrow\)\(2x-15=0\)
Hoặc \(\left(2x-15\right)^{12}=1\)
\(\Leftrightarrow\)\(2x=15\)
Hoặc \(\orbr{\begin{cases}2x-15=1\\2x-15=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=16\\2x=14\end{cases}}}\)
\(\Leftrightarrow\)\(x=\frac{15}{2}=7,5\)
Hoặc \(\orbr{\begin{cases}x=\frac{16}{2}\\x=\frac{14}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=8\\x=7\end{cases}}}\)
Vậy \(x=7\)\(;\)\(x=7,5\) hoặc \(x=8\)
Chúc bạn học tốt ~
\(a,3^6=3^{2.3}=\left(3^2\right)^3=9^3.\)
\(6^3=6^3\)
Vì \(9^3>6^3\Rightarrow3^6>6^3\)
\(b,5^{30}=5^{3.10}=\left(5^3\right)^{10}=125^{10}\)
\(124^{10}=124^{10}\)
Vì \(125^{10}>124^{10}\Rightarrow5^{30}>124^{10}\)
\(c,3^{21}=3^{20}.3^1=3^{2.10}.3=9^{10}.3\)
\(2^{31}=2^{30}.2^1=2^{3.10}.2=8^{10}.2\)
Vì \(9^{10}+3>8^{10}+2\Rightarrow3^{21}>2^{31}\)
\(e,5^{28}=5^{2.14}=\left(5^2\right)^{14}=25^{14}\)
\(26^{14}=26^{14}\)
Vì \(25^{14}< 26^{14}\Rightarrow5^{28}< 26^{14}\)
\(f,27^5=\left(3^3\right)^5=3^{15}\)
\(243^3=\left(3^5\right)^3=3^{15}\)
Vì \(3^{15}=3^{15}\Rightarrow27^5=243^3\)
\(g,3^{500}=3^{5.100}=\left(3^5\right)^{100}=243^{100}\)
\(7^{300}=7^{3.100}=\left(7^3\right)^{100}=343^{100}\)
Vì \(243^{100}< 343^{100}\Rightarrow3^{500}< 7^{300}\)
a,36và 63
3^6=3^3.3^3
6^3=(2.3)^3=2^3.3^3
vi 3^3.3^3>2^3.3^3
nen 3^6>6^3
\(a,[\left(8.x-12\right):4].3^3.3=3^6.6\)
\(\left(8x-12\right):4=54\)
\(8x-12=216\)
\(8x=228\)
\(x=28,5\)
\(b,41-2^{x+1}=9\)
\(2^{x+1}=41-9\)
\(2^{x+1}=32\)
\(2^{x+1}=2^5\)
\(\Rightarrow x+1=5\)
\(\Rightarrow x=4\)
\(\left(x-6\right)^2=9=3^2=\left(-3\right)^2=>\orbr{\begin{cases}x-6=3\\x-6=-3\end{cases}}=>\orbr{\begin{cases}x=9\\x=3\end{cases}}\)
\(5^{x+1}=125=5^3=>x+1=3=>x=2\)
\(5^{2x-3}-2.5^2=3.5^2=>5^{2x-3}=3.5^2+2.5^2=\left(3+2\right).5^2=5.5^2=125=5^3\)
\(=>2x-3=3=>2x=6=>x=3\)