问题
解答题
先化简,再求值.(x-3)(x-1)-(2x-1)2,其中x=
|
答案
(x-3)(x-1)-(2x-1)2,
=x2-4x+3-4x2+4x-1,
=-3x2+2.
当x=
时,原式=-3×5+2=-13.5
先化简,再求值.(x-3)(x-1)-(2x-1)2,其中x=
|
(x-3)(x-1)-(2x-1)2,
=x2-4x+3-4x2+4x-1,
=-3x2+2.
当x=
时,原式=-3×5+2=-13.5