# How do you graph y=-1/2x +b?

For $y = \equiv \frac{1}{2} x + b$ the $y$-intercept is $\left(0 , b\right)$, which is a pretty generic point that depends on the value of $b$.
The slope of the line is $- \frac{1}{2}$ so if $x$ increases by 2, $y$ must decrease by 1.
To graph this line, plot the point $\left(0 , b\right)$ and find a second point at $\left(2 , b - 1\right)$, draw your line through those points.