y=(5x-2)/(4x-3) 求值域
y=(5x-2)/(4x-3)
=[(5/4)(4x-3)+7/4]/(4x-3)
=5/4+7/4(4x-3)
y≠5/4
第二行[(5/4)(4x-3)+7/4]/(4x-3)是怎么来的?