Question

(3x-5)^2-4=0

Answer 1

(3x - 5)² - 4 = 0

<=> 9x² - 30x + 25 - 4 = 0

<=> 9x² - 30x + 21 = 0

<=> 3x² - 10x + 7 = 0

<=> 3x² - 3x - 7x + 7 = 0

<=> 3x(x - 1) - 7(x - 1) = 0

<=> (x - 1)(3x - 7) = 0

<=> \(\left[{}\begin{matrix}x-1=0\\3x-7=0\end{matrix}\right.\) <=> \(\left[{}\begin{matrix}x=1\\x=\dfrac{7}{3}\end{matrix}\right.\)

Vậy tập nghiệm của phương trình là: \(S=\left\{1;\dfrac{7}{3}\right\}\)

 

Answer 2

\(\Leftrightarrow\left(3x-5\right)^2-2^2=0\\ \Leftrightarrow\left(3x-5-2\right)\left(3x-5+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}3x-5-2=0\\3x-5+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{3}\\x=1\end{matrix}\right.\)

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