câu 1 :
(x-1)^2-9=5
(x-1)^2=4
x-1=2 , x = 3
a) (x-1)2 - 9 = -5
⇒ (x-1)2 = -5 +9 = 4
⇒ (x-1)2 = 22
⇒ x-1 = 2
⇒ x = 2 +1= 3
vậy x = 3
b) (3x-1)(-2x+5) = 0
⇒\(\Rightarrow\left\{{}\begin{matrix}3x-1=0\\-2x+5=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}3x=1\\-2x=-5\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=\frac{1}{3}\\x=\frac{5}{2}\end{matrix}\right.\)
vậy x= \(\frac{1}{3}\); x= \(\frac{5}{2}\)
a)(x-1)2-9=-5
\(\Rightarrow\)(x-1)2=-5+9
(x-1)2=4
(x-1)2=22=(-2)2
\(\left[{}\begin{matrix}x-1=2\\x-1=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)
Vậy,x\(\in\left\{-1,3\right\}\)
b)(3x-1)(-2x+5)=0
\(\Rightarrow\left[{}\begin{matrix}3x-1=0\\-2x+5=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{1}{3}\\x=\frac{5}{2}\end{matrix}\right.\)
Vậy,x\(\in\left\{\frac{1}{3},\frac{5}{2}\right\}\)
\(\left(x-1\right)^2-9=-5\)
\(\left(x-1\right)^2=\left(-5\right)+9\)
\(\left(x-1\right)^2=4=2^2=\left(-2\right)^2\)
\(\Rightarrow\)\(\left[{}\begin{matrix}x-1=2\\x-1=-2\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=2+1\\x=\left(-2\right)+1\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)
Vậy \(x\in\left\{3;-1\right\}\)
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