题目

合并同类项： -5a^b+6ab^-4ab-2a^b+4ab+3
合并同类项,在求代数式的值：
（1）6x+2x^-3X+X^+1,其中x=-5
（2）1/3m-3/2n-5/6n-1/6m,其中m=6,n=3. 拜托拜托

提问时间：2021-03-21

答案

-5a^2b+6ab^2-4ab-2a^2b+4ab+3
=-5a^2b-2a^2b+6ab^2-4ab+4ab+3
=(-5-2)a^2b+6ab^2+3
=-7a^2b+6ab^2+3
6x+2x^2-3x+x^2+1
=6x-3x+2x^2+x^2+1
=3x+3x^2+1
=3*(-5)+3*(-5)^2+1
=-15+75+1
=61
1/3m-3/2n-5/6n-1/6m
=1/3m-1/6m-3/2n-5/6n
=2/6m-1/6m-9/6n-5/6n
=1/6m-14/6n
=1/6m-7/3n
=1/6*6-7/3*3
=1-7
=-6