Giải thích các bước giải:
\[\begin{array}{l}
1,\\
a,\\
3{x^2} - 6x + 3 = 0\\
\Leftrightarrow 3\left( {{x^2} - 2x + 1} \right) = 0\\
\Leftrightarrow 3{\left( {x - 1} \right)^2} = 0\\
\Leftrightarrow x - 1 = 0\\
\Leftrightarrow x = 1\\
b,\\
{x^2} + 7x + 10 = 0\\
\Leftrightarrow \left( {{x^2} + 2x} \right) + \left( {5x + 10} \right) = 0\\
\Leftrightarrow x\left( {x + 2} \right) + 5\left( {x + 2} \right) = 0\\
\Leftrightarrow \left( {x + 2} \right)\left( {x + 5} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x + 2 = 0\\
x + 5 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = - 2\\
x = - 5
\end{array} \right.\\
2,\\
\left( {2x + 3} \right)\left( {x - 2} \right) - 2{x^2}\\
= \left( {2{x^2} - 4x + 3x - 6} \right) - 2{x^2}\\
= \left( {2{x^2} - x - 6} \right) - 2{x^2}\\
= - x - 6
\end{array}\]
