What three points do i graph? y= -2x

one way is to find the intercepts, that is where the graph

crosses the x and y axes
∙
let x = 0, in the equation for y-intercept
∙
let y = 0, in the equation for x-intercept
x
=
0
⇒
y
=
3
←
y-intercept
y
=
0
⇒
−
x
+
3
=
0
⇒
x
=
3
←
x-intercept
Plot the points
(
0
,
3
)
and
(
3
,
0
)
Draw a straight line through them for graph

graph{(y+x-3)((x-0)^2+(y-3)^2-0.04)((x-3)^2+(y-0)^2-0.04)=0 [-10, 10, -5, 5]}

The right answer should be 6 but your not very specific