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a)
(2x+2).(2x+2)=x+18
=> 4x²+4x+4x+4=x+18
=> 4x²+8x+4=x+18
=> 4x²+8x-x=18-4
=> 4x²-7x=14
=> x(4x-7)=14
Th1
x=14 => x=14
Th2
x-7=14 => x=21
Vậy x=14 hay 21
b)
(2x+8)(2x+8)+4x=16
=> (4x²+16x+16x+64)+4x=16
=> 4x²+32x+64+4x=16
=> 4x²+38x=16-64
=> x(4x+38)=-48
Th1
X=-48 => x=-48
Th2
4x+38=-48 => 4x=10 => x=2,5
Vậy.....
\(x^2-0,25=0\)
\(\Leftrightarrow x^2-0,5^2=0\)
\(\Leftrightarrow x-0,5=0\)
\(\Leftrightarrow x=0+0,5\)
\(\Leftrightarrow x=0,5\)
b.
\(\dfrac{8}{2x}=2\Leftrightarrow2x=\dfrac{8}{2}\Rightarrow x=4:2=2\)
c.
\(\left(2x-1\right)^3=8\)
\(\Rightarrow\left(2x-1\right)^3=2^3\)
\(\Rightarrow2x-1=2\)
\(\Rightarrow2x=2+1\)
\(\Rightarrow2x=3\)
\(\Rightarrow x=\dfrac{3}{2}\)
d.
\(\left(x-2\right)^2=16\)
\(\Rightarrow\left(x-2\right)^2=4^2\)
\(\Rightarrow x-2=4\)
\(\Rightarrow x=4+2\)
\(\Rightarrow x=6\)
Chúc bạn học tốt!!!!
\(x^2-0,25=0\)
\(\Rightarrow x^2=0,25\)
\(\Rightarrow x=0,5\)
b. \(\dfrac{8}{2x}=2\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=2\)
c. \(\left(2x-1\right)^3=8\)
\(\left(2x-1\right)^3=2^3\)
\(\Rightarrow2x-1=2\)
\(\Rightarrow x=\dfrac{3}{2}\)
d. \(\left(x-2\right)^2=16\)
\(\left(x-2\right)^2=\pm4^2\)
\(\Rightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)
a) \(2^{4x+1}-8^{x+2}=0\)\(\Leftrightarrow2^{4x+1}-2^{3\left(x+2\right)}=0\)
\(\Leftrightarrow2^{4x+1}-2^{3x+6}=0\)\(\Leftrightarrow2^{4x+1}=2^{3x+6}\)
\(\Leftrightarrow4x+1=3x+6\)\(\Leftrightarrow4x-3x=6-1\)\(\Leftrightarrow x=5\)
Vậy \(x=5\)
b) \(3^2.9^{2x}=27^{x+3}\)\(\Leftrightarrow3^2.3^{2.2x}=3^{3\left(x+3\right)}\)\(\Leftrightarrow3^2.3^{4x}=3^{3x+9}\)
\(\Leftrightarrow3^{2+4x}=3^{3x+9}\)\(\Leftrightarrow2+4x=3x+9\)\(\Leftrightarrow4x-3x=9-2\)\(\Leftrightarrow x=7\)
Vậy \(x=7\)
c) \(8^{2x}.64^2=16^{x+4}\)\(\Leftrightarrow2^{3.2x}.2^{6.2}=2^{4\left(x+4\right)}\)\(\Leftrightarrow2^{6x}.2^{12}=2^{4\left(x+4\right)}\)
\(\Leftrightarrow2^{6x+12}=2^{4x+16}\)\(\Leftrightarrow6x+12=4x+16\)\(\Leftrightarrow6x-4x=16-12\)
\(\Leftrightarrow2x=4\)\(\Leftrightarrow x=2\)
Vậy \(x=2\)
a) \(4^{2x-6}=1\)
\(\Rightarrow4^{2x-6}=4^0\)
\(\Rightarrow2x-6=0\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
b) \(2^{x-1}=16\)
\(\Rightarrow2^{x-1}=2^4\)
\(\Rightarrow x-1=4\)
\(\Rightarrow x=5\)
c) \(5< 5x< 125\)
\(\Rightarrow\frac{5}{5}< \frac{5x}{5}< \frac{125}{5}\)
\(\Rightarrow1< x< 25\)
\(\Rightarrow\left\{x\inℤ|1< x< 25\right\}\)
d) mk không hiểu
|2x| + |-2x| = 16
=> 2x + (-2x) = 16
và 2x + 2x = 16
=> 0 = 16 ( loại ) và 4x = 16
=> x = 4
\(\frac{16}{2x}=2\)
\(2x=\frac{16}{2}\)
\(2x=8\)
\(\Rightarrow x=8:2\)
\(x=4\)
\(\frac{16}{2x}=2\)
\(2x=16:2\)
\(\) \(2x=8\)
\(x=4\)
\(\)Vậy x = 4
\(\frac{16}{2}x\) hay \(\frac{16}{2x}\) em nhỉ?
\(\frac{16}{2x}\)=\(2\)
\(2x=16:2\)
\(2x=8\)
\(x=8:2\)
\(x=4\)
Vậy x = 4