若式子(2x+3ax-y)-2(bx-3x+2y-1)的值与字母x的取值无关,则式子(a-b)-(a+b)的值是__数学解答

若式子(2x+3ax-y)-2(bx-3x+2y-1)的值与字母x的取值无关,则式子(a-b)-(a+b)的值是_

人气：489 ℃　时间：2019-08-21 07:47:42

解答

(2x^2+3ax-y)-2(bx^2-3x+2y-1) =2x+3ax-y-2bx+6x-4y+2 =(2-2b)x+(3a+6)x-5y+2 与字母x的取值无关则2-2b=0,3a+6=0 则b=1,a=-2