先化简再求值:(x+5)^2-(x-5)^2-5(2x+1)(2x-1)+x(2x)^2,其中x=1,
问题描述:
先化简再求值:(x+5)^2-(x-5)^2-5(2x+1)(2x-1)+x(2x)^2,其中x=1,
答
(x+5)^2-(x-5)^2-5(2x+1)
=20x-10x-5
=10x-5
=10-5
=1
(2x-1)+x(2x)^2
=4x^3+2x-1
=4+2-1
=5