问题 解答题

3(x-2)2(x-7)+11(2-x)(7-x),其中x=1.

答案

3(x-2)2(x-7)+11(2-x)(7-x)

=3(x2-4x+4)(x-7)+11(x2-9x+14)

=3x3-21x2-12x2+84x+12x-84+11x2-99x+154

=3x3-22x2-3x+70,

当x=1时,原式=3×13-22×12-3×1+70

=48.

单项选择题
单项选择题