题目

化简：2x^2-3[2x-2(-x^2+2x-1)-4]
3/4[4/3(1/3x-1)-8]-(-2/3x-5)
合并同类项：
1/2+1/2x^2+1/2xy+1/2x^2y-1/3x^2-1/3xy-1/3x^2y
5a^n-2a^n-8a^n+1+6a^n-a^n+1

提问时间：2021-03-17

答案

3/4[4/3(1/3x-1)-8]-(-2/3x-5)
＝(1/3x-1)-6+2/3x+5
＝1/3x-1-6+2/3x+5
＝ x-2
合并同类项：
1/2+1/2x^2+1/2xy+1/2x^2y-1/3x^2-1/3xy-1/3x^2y
=1/2+(1/2x^2-1/3x^2)+(1/2xy-1/3xy)+(1/2x^2y-1/3x^2y )
=1/2+1/6x^2+1/6xy+1/6x^2y
5a^n-2a^n-8a^n+1+6a^n-a^n+1
=(5-2-8+6-1)a^n+2
=0+2
=2