Question

利用公式法解决下题：a^3-4a^2+4a

Answer 1

a^3-4a^2+4a

=a(a^2-4a+4)

=a(a-2)^2

(x+y）^2-6(x+y)+9

=(x+y-3)^2

(m^2+n2)^2-4m^2n^2

=(m^2+n^2+2mn)(m^2+n^2-2mn)

=(m+n)^2(m-n)^2