(x-2)(x-3)+2(x+6)(x-5)-3(x²-7x+13),再求其值,其中x=3½.

问题描述:

(x-2)(x-3)+2(x+6)(x-5)-3(x²-7x+13),再求其值,其中x=3½.

(x-2)(x-3)+2(x+6)(x-5)-3(x²-7x+13)
=(x²-5x+6)+2(x²+x-30)-3(x²-7x+13)
=x²-5x+6+2x²+2x-60-3x²+21x-39
=18x-93
=18*(3½)-93
=18*(7/2)-93
=63-93
=-30