函数y=(5x-2)/(4x+2)的值域
= (5x+2x5/4 - 2x5/4 -2 ) / (4x+2)
= (5x+2x5/4 - 5/2 -2 ) / (4x+2)
= (5x+2x5/4 - 9/2 ) / (4x+2)
= 5/4 - 9/2 / (4x+2)
的值域 为 y≠ 4分之 5