Question

Giải phương trình:

 

(3x-1)² -3(3x-2)=9(x+1)(x-3)

Answer 1

PT \(\Leftrightarrow9x^2-6x+1-9x+6=9x^2-18x-27\)

\(\Leftrightarrow9x^2-6x+1-9x+6-9x^2+18x+27=0\)

\(\Leftrightarrow3x+34=0\)

\(\Leftrightarrow x=-\dfrac{34}{3}\)

Vậy ...

Answer 2

Ta có: \(\left(3x-1\right)^2-3\left(3x-2\right)=9\left(x+1\right)\left(x-3\right)\)

\(\Leftrightarrow9x^2-6x+1-9x+6=9\left(x^2-3x+x-3\right)\)

\(\Leftrightarrow9x^2-15x+7=9x^2-18x-27\)

\(\Leftrightarrow9x^2-15x+7-9x^2+18x+27=0\)

\(\Leftrightarrow3x+34=0\)

\(\Leftrightarrow3x=-34\)

\(\Leftrightarrow x=-\dfrac{34}{3}\)

Vậy: \(S=\left\{-\dfrac{34}{3}\right\}\)