Question

因式分解：9-x²-4y²+4xy x²-4y²+16y-16

Answer 1

9-x²-4y²+4xy

=9-(x^2+4y^2-4xy)

=9-(x-2y)^2

=(3+x-2y))*(3-x+2y)

x²-4y²+16y-16

=x^2-(4y^2-16y+16)

=x^2-(2y-4)^2

=(x+2y-4)*(x-2y+4)