Question

和大家对一下答案，因式分解： -27m²n+9mn²-18mn x四次方-16

（2a+3b）²-（3a-2b）² 8y四次方-2y²
2x（x+y）²-（x+y）³ -24x²y-12xy²+28y³

Answer 1

-27m^2n+9mn^2-18mn
=9mn(n-3m-2)
x^4-16
=(x^2+4)(x^2-4)
=(x^2+4)(x+2)(x-2)
(2a+3b)^2-(3a-2b)^2
=(2a+3b+3a-2b)(2a+3b-3a+2b)
=(5a+b)(5b-a)
8y^4-2y^2
=2y^2(4y^2-1)
=2y^2(2y+1)(2y-1)
2x(x+y)^2-(x+y)^3
=(x+y)^2(2x-x-y)
=(x+y)^2(x-y)
-24x^2y-12xy^2+28y^3
=4y(7y^2-3xy-6x^2)