Đáp án:
$\begin{array}{l}
2)3{x^2} + 3x - 6\\
= 3.\left( {{x^2} + x - 2} \right)\\
= 3\left( {{x^2} + 2x - x - 2} \right)\\
= 3\left( {x - 1} \right)\left( {x + 2} \right)\\
4)6{x^2} - 13x + 6\\
= 6{x^2} - 9x - 4x + 6\\
= \left( {2x - 3} \right)\left( {3x - 2} \right)\\
6)6{x^2} + 15x + 6\\
= 6{x^2} + 12x + 3x + 6\\
= 3\left( {x + 2} \right)\left( {2x + 1} \right)\\
8)6{x^2} + 20x + 6\\
= 2.\left( {3{x^2} + 10x + 3} \right)\\
= 2.\left( {3x + 1} \right)\left( {x + 3} \right)\\
10)6{x^2} + 12x + 6\\
= 6\left( {{x^2} + 2x + 1} \right)\\
= 6{\left( {x + 1} \right)^2}\\
12)8{x^2} + 2x - 3\\
= 8{x^2} + 6x - 4x - 3\\
= \left( {4x + 3} \right)\left( {2x - 1} \right)\\
14)8{x^2} - 10x - 3\\
= 8{x^2} - 12x + 2x - 3\\
= \left( {2x - 3} \right)\left( {4x + 1} \right)\\
16) - 8{x^2} + 23x + 3\\
= - 8{x^2} + 24x - x + 3\\
= \left( { - x + 3} \right)\left( {8x + 1} \right)\\
18)10{x^2} - 11x - 6\\
= 10{x^2} - 15x + 4x - 6\\
= \left( {2x - 3} \right)\left( {5x + 2} \right)\\
20)10{x^2} - 4x - 6\\
= 2.\left( {5{x^2} - 2x - 3} \right)\\
= 2.\left( {5{x^2} - 5x + 3x - 3} \right)\\
= 2.\left( {x - 1} \right)\left( {5x + 3} \right)\\
22)10{x^2} + 7x - 6\\
= 10{x^2} + 12x - 5x - 6\\
= \left( {5x + 6} \right)\left( {2x - 1} \right)
\end{array}$
$\begin{array}{l}
24)\\
10{x^2} + 17x - 6\\
= 10{x^2} + 20x - 3x - 6\\
= 10x\left( {x + 2} \right) - 3\left( {x + 2} \right)\\
= \left( {x + 2} \right)\left( {10x - 3} \right)\\
26) - 10{x^2} + 28x + 6\\
= - 10{x^2} + 30x - 2x + 6\\
= - 10x\left( {x - 3} \right) - 2\left( {x - 3} \right)\\
= - 2.\left( {x - 3} \right)\left( {5x + 1} \right)\\
28)10{x^2} - 7x - 12\\
= 10{x^2} - 15x + 8x - 12\\
= \left( {2x - 3} \right)\left( {5x + 4} \right)\\
30)10{x^2} - 14x - 12\\
= 2.\left( {5{x^2} - 7x - 6} \right)\\
= 2.\left( {5{x^2} - 10x + 3x - 6} \right)\\
= 2.\left( {x - 2} \right)\left( {5x + 3} \right)
\end{array}$
