(2m+n)²-2(2m+n)(2m-n)
=(2m+n)[(2m+n) -2(2m-n)]
=(2m+n)(-2m+3n)
.
(-2x²)的3次方-x的5次方·x-x的7次方/x
=-8x的6次幂 - x的6次幂 - x的6次幂
=-10x的6次幂
(2m+n)²-2(2m+n)(2m-n)
=(2m+n)[(2m+n) -2(2m-n)]
=(2m+n)(-2m+3n)
.
(-2x²)的3次方-x的5次方·x-x的7次方/x
=-8x的6次幂 - x的6次幂 - x的6次幂
=-10x的6次幂