题目:
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.
3(x-2)2(x-7)+11(2-x)(7-x),其中x=1.
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.