3/4 - 4z + 5/4z - 1/2 + 1/2z

First group the terms with the variables and those without so you'll get (-4z+5/4z+1/2z) + (3/4-1/2). Then, get the LCD of the terms so you'll have the terms (-16z+5z+2z) + (3-2). Lastly, since it has a common LCD, you'll be able to get the answer of - 9z+1.