(x-1,2)2=4
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![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(2^x=8\)
⇔ \(2^x=2^3\)
⇒ \(x=3\)
b) \(3^x=27\)
⇔ \(3^x=3^3\)
⇒ \(x=3\)
c) \(\left(-\dfrac{1}{2}\right)x=\left(-\dfrac{1}{2}\right)^4\)
⇔ \(x=\left(-\dfrac{1}{2}\right)^4\div\left(-\dfrac{1}{2}\right)\)
⇔ \(x=\left(-\dfrac{1}{2}\right)^3\)
d) \(x\div\left(-\dfrac{3}{4}\right)=\left(-\dfrac{3}{4}\right)^2\)
⇔ \(x=\left(-\dfrac{3}{4}\right)^2\cdot\left(-\dfrac{3}{4}\right)\)
⇔ \(x=\left(-\dfrac{3}{4}\right)^3=-\dfrac{27}{64}\)
d) \(\left(x+1\right)^3=-125\)
⇔ \(\left(x+1\right)^3=\left(-5\right)^3\)
⇔ \(x+1=-5\)
⇔ \(x=-5-1=-6\)
2:
a: (x-1,2)^2=4
=>x-1,2=2 hoặc x-1,2=-2
=>x=3,2(loại) hoặc x=-0,8(loại)
b: (x-1,5)^2=9
=>x-1,5=3 hoặc x-1,5=-3
=>x=-1,5(loại) hoặc x=4,5(loại)
c: (x-2)^3=64
=>(x-2)^3=4^3
=>x-2=4
=>x=6(nhận)
![](https://rs.olm.vn/images/avt/0.png?1311)
A) 65,46 x 1,2 + 33,54 x 1,2 + 1,2
= 1,2 x ( 65, 46 + 33,54 + 1 )
= 1,2 x 100
= 120
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\(\left(x-1,2\right)^2=4\)
\(\left(x-1,2\right)^2=2^2\)
\(\Rightarrow\orbr{\begin{cases}x-1,2=2\\x-1,2=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=3,2\\x=-0,8\end{cases}}}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Từ đề bài suy ra x - 1,2 = 2 hoặc x - 1,2= -2. Tìm được
x ∈ {-0,8;3,2}
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(x-1,2\right)^2=4\)
\(\left(x-1,2\right)^2=2^2\)
\(\Rightarrow\orbr{\begin{cases}x-1,2=2\\x-1,2=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=3,2\\x=-0,8\end{cases}}}\)
\(\left(x+1\right)^3=-125\)
\(\left(x+1\right)^3=\left(-5\right)^3\)
\(x+1=-5\)
\(x=-6\)
\(a,\left(x-1,2\right)^2=4\)
\(x-1,2=\pm2\)
\(\orbr{\begin{cases}x-1,2=2\\x-1,2=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=3,2\\x=-\frac{4}{5}\end{cases}}}\)
\(b,\left(x+1\right)^3=-125\)
\(x+1=-5\)
\(x=-6\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a,\(\dfrac{2}{3}x-\dfrac{4}{9}=-\dfrac{5}{27}\)
\(\dfrac{2}{3}x=\dfrac{17}{27}\)
\(x=\dfrac{17}{18}\)
b,\(\dfrac{2}{3}x+\dfrac{4}{9}=\dfrac{5}{27}\)
\(\dfrac{2}{3}x=-\dfrac{7}{27}\)
\(x=-\dfrac{7}{18}\)
c,\(x:1,2=5,4:6\)
\(x:1,2=0,9\)
\(x=1,08\)
d,\(1,68:1,2=5,4:x\)
\(1,4=5,4:x\)
\(x=\dfrac{27}{7}\)
e,\(\left(1-2x\right)^2+1=10\)
\(\left(1-2x\right)^2=9\)
\(1-2x=3\)
\(2x=-2\)
\(x=-1\)
f,\(\left(1-2x\right)^2-6=10\)
\(\left(1-2x\right)^2=16\)
\(1-2x=4\)
\(2x=-3\)
\(x=-\dfrac{3}{2}\)
\(\left(x-1,2\right)^2=4\)
\(\left(x-1,2\right)^2=2^2\)
\(x-1,2=2\)
\(x=2+1,2\)
\(x=3,2\)
Vậy `x = 3,2`
(x-1/2)^2 = 4
GTTĐ |x-1/2|=2
suy ra x-1/2=+-2
Th1:x-1/2=2
Th2:x-1/2=-2
giải nốt tìm x có 2 gtri