Đáp án:
$\displaystyle \begin{array}{{>{\displaystyle}l}} b1.\ ( -3x+2)( 2x-1)\\ b2.\ ( x-2)( -3x+1)\\ b3.\ ( x-2)( 2x-1)\\ b4.\ ( 3x-2)( x-2)\\ b5.\ ( 3x-1)( 2x-3\\ b6.\ 2( x+4)( x-3)\\ b7.\ ( x-1)( 4x-1) \end{array}$
Giải thích các bước giải:
$\displaystyle \begin{array}{{>{\displaystyle}l}} b1.\ A=7x-6x^{2} -2=-6x^{2} +3x+4x-2\\ =-3x( 2x-1) +2( 2x-1) =( -3x+2)( 2x-1)\\ b2.\ A=7x-3x^{2} -2=-3x^{2} +6x+x-2\\ =-3x( x-2) +( x-2) =( x-2)( -3x+1)\\ b3.\ A=2x^{2} +2-5x=2x^{2} -4x-x+2\\ =2x( x-2) -( x-2) =( x-2)( 2x-1)\\ b4.\ A=-8x+4+3x^{2} =3x^{2} -6x-2x+4\\ =3x( x-2) -2( x-2) =( 3x-2)( x-2)\\ b5.\ A=3+6x^{2} -11x=6x^{2} -2x-9x+3\\ =2x( 3x-1) -3( 3x-1) =( 3x-1)( 2x-3)\\ b6.\ A=2x^{2} -27+3x=2x^{2} -6x+9x-27\\ =2x( x-3) +8( x-3) =2( x+4)( x-3)\\ b7.\ A=-5x+4x^{2} +1=4x^{2} -4x-x+1\\ =4x( x-1) -( x-1) =( x-1)( 4x-1) \end{array}$