Câu 1 ) a)\(x^2-6x+7=x^2-6x+9-2=\left(x-3\right)^2-\sqrt{2}^2\)
=(x-3-\(\sqrt{2}\))\(\left(x-3+\sqrt{2}\right)\)
b)\(y^2+y-20\)=\(y^2-4y-5y+20\)
=y(y-4)-5(y-4)
=(y-4)(y-5)
c)\(2x^2-x-6\)=\(2x^2-4x+3x-6=2x\left(x-2\right)+3\left(x-2\right)\)
=(2x+3)(x-2)
d)\(3m^2+2m-8=3m^2+6m-4m-8\)
=3m(m+2)-4(m+2)
=(3x-4)(m+2)
2)
a)\(4a^2+8a-3a-6=4a\left(a+2\right)-3\left(a+2\right)\)
= \(\left(4a-3\right)\left(a+2\right)\)
b)\(3x^2+13x+14=3x^2+6x+7x+14\)
=3x(x+2)+7(x+2)
=(3x+7)(x+2)\(2m^2-3m-27=2m^2+6m-9m-27\)
=2m(m+3)-9(m+3)
=(2m-9)(m+3)