3x=243
5.52x+1=625
(6-3x).(311-3x-243)=0
(12-2x)3=23.33
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`@` `\text {Ans}`
`\downarrow`
`2^x = 16`
`=> 2^x = 2^4`
`=> x = 4`
Vậy, `x = 4.`
____
`2^x*16 = 1024`
`=> 2^x =`\(2^{10}\div2^4\)
`=> 2^x = 2^6`
`=> x = 6`
Vậy, `x = 6`
______
`2^x - 26 = 6`
`=> 2^x = 6 + 26`
`=> 2^x = 32`
`=> 2^x = 2^5`
`=> x = 5`
Vậy, `x = 5`
`3^x*3 = 243`
`=> 3^x * 3 = 3^5`
`=> 3^x = 3^5 \div 3`
`=> 3^x = 3^4`
`=> x = 4`
Vậy, `x = 4.`
a)2x.2x+1=128
\(4x^2+1=128\)
\(\Rightarrow4x^2=127\)
\(\Rightarrow x^2=127\div4\)
\(\Rightarrow x^2=3.175\)
mà \(x\in N\) hay\(x^2\in N\)
\(\Rightarrow\)Không có x
b) 3x+1.3x=243
\(\Rightarrow\)3x+3x=243
\(\Rightarrow\)6x=243
\(\Rightarrow\)x=40,5
Mà \(x\in N\)
\(\Rightarrow\)Không có x
a) \(\left(2x-1\right)^5=243\)
\(\left(2x-1\right)^5=3^5\)
\(\Rightarrow2x-1=3\)
\(2x=3+1\)
\(2x=4\)
\(x=\frac{4}{2}\)
\(x=2\)
Vậy .......
b) \(\left(3x+2\right)^3=125\)
\(\left(3x+2\right)^3=5^3\)
\(\Rightarrow3x+2=5\)
\(3x=5-2\)
\(3x=3\)
\(x=\frac{3}{3}=1\)
Vậy ..........
a) \(2^x\cdot4=16\)
\(\Rightarrow2^x=16:4\)
\(\Rightarrow2^x=4\)
\(\Rightarrow2^x=2^2\)
\(\Rightarrow x=2\)
b) \(3^x\cdot3=243\)
\(\Rightarrow3^x=243:3\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
\(Bài.44:\\ a,3x-7=0\\ \Leftrightarrow3x=7\\ \Leftrightarrow x=\dfrac{7}{3}\\ b.2x^2+9=0\\ \Leftrightarrow x^2=-\dfrac{9}{2}\left(vô.lí\right)\\ \Rightarrow Không.có.x.thoả.mãn\)
43:
a: \(A=2x\left(x^2-2x-3\right)-6x^2+5x-1+9x^2+3x+3\)
\(=2x^3-4x^2-6x+3x^2+8x+2\)
\(=2x^3-x^2+2x+2\)
b: \(\dfrac{A}{2x-1}=\dfrac{x^2\left(2x-1\right)+2x-1+3}{2x-1}=x^2+1+\dfrac{3}{2x-1}\)
Thương là x^2+1
Dư là 3
c: A chia hết cho 2x-1
=>3 chia hết cho 2x-1
=>2x-1 thuộc {1;-1;3;-3}
=>x thuộc {1;0;2;-1}
a) 3x = 243
=> 3x = 35
=> x = 5
b) 5.52x+1 = 625
=> 52x+2 = 54
=> 2x+2 = 4
=> 2x = 2
=> x = 1
c) (6-3x)(311-3x-243)=0
\(\Rightarrow\left[{}\begin{matrix}6-3x=0\\3^{11-3x}-243=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}3x=6\\3^{11-3x}=243=3^5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\11-3x=5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2\\3x=6\end{matrix}\right.\Rightarrow x=2\)
d) (12-2x)3=23.33
=> (12-2x)3=(2.3)3
=> (12-2x)3=63
=> 12-2x=6
=> 2x=6
=> x = 3