#### Answer

$y=.5x-1.5$ (most useful if we needed the y-intercept or a slope)
$x+2y=3$ (most useful if no slope is needed or if two points aren't given)
$y+1 = .5(x-1)$ (most helpful when given a graph or two points on a line)

#### Work Step by Step

$m=.5$, $(1, -1)$
$y=mx+b$
$-1 = .5*1+b$
$-1 = .5+b$
$-1-.5 = .5+b-.5$
$-1.5 = b$
$y=.5x-1.5$
$y=.5x-1.5$
$2*(y=.5x-1.5)$
$2y=x-3$
$2y+3-2y=x-3+2y$
$3 = x+2y$