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

[-(4x-6)]-[-(4y-6)]
=(6-4x)-(6-4y)
=6-4x-6+4y
=4y-4x
=4(y-x)
∵x∴y-x>0
∴[-(4x-6)]-[-(4y-6)]=4(y-x)>0
即-(4x-6)>-(4y-6)