试说明 {A+3A+4A-1}+{A-3A+A-3}+{8-A-4A-2A}的值于A的取值无关

问题描述:

试说明 {A+3A+4A-1}+{A-3A+A-3}+{8-A-4A-2A}的值于A的取值无关

(A+3A+4A-1)+(A-3A+A-3)+(8-A-4A-2A) =A+3A+4A-1+A-3A+A-3+8-A-4A-2A =A+A-2A+3A+A-4A+4A-3A-A-1-3+8 =-1-3+8 =4 ∵原式等于常数,∴该式的值于A的取值无关.