Question

Bài mik để dưới phần trả lời ạ

Answer 1

  đây nha

Answer 2

17:x^2-9=(x-3)(x+3)

18: 4x^2-25=(2x-5)(2x+5)

19: =(x^2-y^2)(x^2+y^2)

=(x-y)(x+y)(x^2+y^2)

20: 9x^2+6xy+y^2=(3x+y)^2

21 6x-9-x^2

=-(x^2-6x+9)

=-(x-3)^2

22: x^2+4xy+4y^2

=x^2+2*x*2y+(2y)^2

=(x+2y)^2

23: =(x+y+x-y)(x+y-x+y)

=2x*2y=4xy

25: =(3x+1+x+1)(3x+1-x-1)

=(4x+2)*2x

=4x(2x+1)

27: =(2x-y)(4x^2+2xy+y^2)-6xy(2x-y)

=(2x-y)(2x-y)^2

=(2x-y)^3