The general form of the equation of a line is given by:
[tex]y=mx+b[/tex]
where m is the slope of the line and b the y-intercept.
You have the following equation:
[tex]y=-\frac{1}{2}x+\frac{1}{4}[/tex]
By comparing the previous equation with the general form you can notice that:
m = -1/2
That is, the slope of the given line is -1/2.
