Question

Giải pt: (2x-3)(2x+3)=2(2x-3)(2x-3)

Giúp cho mik với ạ chứ mik làm sai sai ở đâu ý

 

Answer 1

\(\left(2x-3\right)\left(2x+3\right)=2\left(2x-3\right)\left(2x-3\right)\)

\(\Leftrightarrow\left(2x-3\right)\left(2x+3\right)-2\left(2x-3\right)\left(2x-3\right)=0\)

\(\Leftrightarrow\left(2x-3\right)\left(2x+3-4x+6\right)=0\)

\(\Leftrightarrow\left(2x-3\right)\left(-2x+9\right)=0\)

\(\Leftrightarrow2x-3=0\) hay \(-2x+9=0\)

\(\Leftrightarrow x=\dfrac{3}{2}\) hay \(x=\dfrac{9}{2}\)

-Vậy \(S=\left\{\dfrac{3}{2};\dfrac{9}{2}\right\}\)