Question

Phân tích đa thức thành nhân tử:

1) a) x^2_6x+7

b) y²+y-20

c) 2x²-x-6

d) 3m²+2m-8

2) a) 4a²+5a-6

b) 3x²+13x+14

c) 2m²-3m-27

Các bạn giúp mk nha mk đg cần gấp

Answer 1

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)