[tex]The\ slope-intercept\ form:y=mx+b\\\\m-the\ slope\\----------------------\\\\4x-8y-16=0\ \ \ |add\ 8y\ to\ both\ sides\\\\4x-16=8y\ \ \ \ \ |divide\ both\ sides\ by\ 8\\\\\frac{4}{8}x-\frac{16}{8}=y\\\\y=\frac{1}{2}x-2\\\\Answer:\boxed{m=\frac{1}{2}}[/tex]