Question

若x=-1/6,求代数式2(3x^3-4x^2+5x-6)-7(3x^2-5x-7)+10(-3x^3+2x^2-4x-

Answer 1

2(3x^3-4x^2+5x-6)-7(3x^2-5x-7)+10(-3x^3+2x^2-4x-5

=6x³-8x²+10x-12-21x²+35x+49-30x³+20x²-40x-5 0

=-24x³-9x²+5x-13

当x=-1/6时

原式=24×（1/6）³-9×（1/6）²-5×（1/6）-13

=1/9-9/36-5/6-13

=-503/36