若x>y,比较-(4x-6)与-(4y-6)的大小
问题描述:
若x>y,比较-(4x-6)与-(4y-6)的大小
答
[-(4x-6)]-[-(4y-6)]
=(6-4x)-(6-4y)
=6-4x-6+4y
=4y-4x
=4(y-x)
∵x
∴[-(4x-6)]-[-(4y-6)]=4(y-x)>0
即-(4x-6)>-(4y-6)