Question

一,计算(1)5a^2b*(-2ab^2)^3 (2)(12x^3y-20xy)/4xy二,化简,求值(m+2n)^2-

Answer 1

(1)5a^2b*(-2ab^2)^3

=5a^2b*(-8)*a^3*b^6

=-40*a^5*b^7

(2)(12x^3y-20xy)/4xy

=12x^3y/4xy -20xy/4xy

=3x^2-5

二.

(m+2n)^2-(m-n)(m+3n)

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

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

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

=n*(2m+3n)+4n^2

=21+2√6

还可以吧