Answer
$a.\quad y=-2x$
$b.\quad $slope: $-2, \quad $y-intercept: $0$
$c.\quad $see graph below
.
Work Step by Step
$ a.\quad$
$2x+y=0$
... subtract $2x$
$y=-2x$
$ b.\quad$
Comparing to $y=mx+b,$
the y-intercept is $0$,
the slope is $m=-2=\displaystyle \frac{-2}{1}\quad=\frac{\text{change in y}}{\text{change in x}}$
$ c.\quad$
To obtain a second point, starting with $(0,0)$,
change x by $1$, y by $-2\quad\rightarrow\quad(1,-2)$.
Draw a line through the two points.
