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a, 27.\(3^x\) = 243
\(3^x\) = 243 : 27
\(3^x\) = 9
\(3^x\) = 32
\(x\) = 2
b, 49.7\(^x\) = 2041
7\(^x\) = 2041: 49
7\(^x\) = 41,65
\(x\) = log741,56
\(x\) ≈ 1,916
c, 64.4\(^x\) = 4\(^5\)
4\(^x\) = 45 : 64
4\(^x\) = 4
\(x\) = 1
d, 3\(^x\) = 243
3\(^x\) = 35
\(x\) = 5
e, 2\(^{x+5}\) = 128
\(2^{x+5}\) = 27
\(x+5\) = 7
\(x\) = 7 - 5
\(x\) = 2
f, 3.3\(^x\) = 81
3\(^x\) = 81 : 3
3\(^x\) = 27
3\(^x\) = 33
\(x\) = 3
g, 25 + 5\(^x\).5\(^x\) = 650
5\(^{2x}\) = 650 - 25
5\(^{2x}\) = 625
5\(^{2x}\) = 54
2\(x\) = 4
\(x\) = 2
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a: Kẻ Ox//AB
Ox//AB
=>góc xOA=góc OAB(hai góc so le trong)
=>góc xOA=41 độ
góc xOA+góc xOB=góc AOB
=>góc xOB=71-41=30 độ=góc OCD
=>Ox//CD
=>AB//CD
=>Ax//Cy
b: BD//AO
=>góc B+góc OAB=180 độ(trong cùng phía)
=>góc B=180-41=139 độ
AB//CD
=>góc B+góc D=180 độ(hai góc trong cùng phía)
=>góc D=180-139=41 độ
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better not eat too much junk food
been reading that book for 2 weeks
When I arrived last night, he was watching TV
going to bed late last night, she felt tired
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\(a,27.3^x=243\\ \Rightarrow3^x=243:27\\ \Rightarrow3^x=9\\ \Rightarrow3^x=3^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(b,49.7^x=2041\\ \Rightarrow7^x=2041:49\\ \Rightarrow7^x=7^4:7^2\\ \Rightarrow7^x=7^{4-2}\\ \Rightarrow7^x=7^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(c,64.4^x=4^5\\ \Rightarrow4^x=4^5:4^3\\ \Rightarrow4^x=4^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(d,3^x=243\\ \Rightarrow3^x=3^5\\ \Rightarrow x=5\left(thoaman\right)\)
\(e,2^{x+5}=128\\ \Rightarrow2^x.2^5=2^7\\ \Rightarrow2^x=2^7:2^5\\ \Rightarrow2^x=2^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(f,3.3^x=81\\ \Rightarrow3^x=81:3\\ \Rightarrow3^x=27\\ \Rightarrow3^x=3^3\\ \Rightarrow x=3\left(thoaman\right)\)
\(g,25+5^x.5^x=650\\ \Rightarrow5^{2x}=650-25\\ \Rightarrow5^{2x}=625\\ \Rightarrow5^{2x}=5^4\\ \Rightarrow2x=4\\ \Rightarrow x=4:2=2\left(thoaman\right)\)
câu h không rõ đề ?
@seven
k) \(125^5:25^3\)
\(=\left(5^3\right)^5:\left(5^2\right)^3\)
\(=5^{15}:5^6\)
\(=5^{15-6}\)
\(=5^9\)
l) \(27^6:9^3\)
\(=\left(3^3\right)^6:\left(3^2\right)^3\)
\(=3^{18}:3^6\)
\(=3^{18-6}\)
\(=3^{12}\)
m) \(4^{20}:2^{15}\)
\(=\left(2^2\right)^{20}:2^{15}\)
\(=2^{40}:2^{15}\)
\(=2^{40-15}\)
\(=2^{25}\)
n) \(24^n:2^{2n}\)
\(=6^n\cdot4^n:\left(2^2\right)^n\)
\(=6^n\cdot4^n:4^n\)
\(=6^n\)
p) \(64^4\cdot16^5:4^{20}\)
\(=\left(4^3\right)^4\cdot\left(4^2\right)^5:4^{20}\)
\(=4^{12}\cdot4^{10}:4^{20}\)
\(=4^{12+10-20}\)
\(=4^2\)
q) \(32^4:8^6\)
\(=\left(2^5\right)^4:\left(2^3\right)^6\)
\(=2^{20}:2^{18}\)
\(=2^{20-18}\)
\(=2^2\)
k: =(5^3)^5:(5^2)^3
=5^15:5^6=5^9
l: =(3^3)^6:(3^2)^3
=3^18:3^6=3^12
m: =2^40:2^15=2^25
n: \(=\dfrac{24^n}{4^n}=6^n\)
p: \(=\left(4^3\right)^4\cdot\dfrac{\left(4^2\right)^5}{4^{20}}=\dfrac{4^{12}\cdot4^{10}}{4^{20}}=4^2\)
q: \(=\left(2^5\right)^4:\left(2^3\right)^6=\dfrac{2^{20}}{2^{18}}=2^2\)