determine parallel, perpendicular or neither

[mikey13]

determine parallel, perpendicular or neither:

2x+y=3 and y=1-2x

I am confused as to where to start

 

[Mrspi]

2x+y=3 and y=1-2x

I am confused as to where to start

Start by finding the slopes of the given lines.

THEN.....

1) if the slopes are the same, the lines are parallel (or the same line, if the y-intercepts are also the same)

2) if the slopes are OPPOSITE RECIPROCALS (or, put another way, if the product of the two slopes is -1), then the lines are perpendicular.

3) if the slopes are not the same, and they are not opposite reciprocals either, then the lines are neither perpendicular nor parallel.

 

[mikey13]

do you sovel for y first, confused

2x+y=3 and y=1-2x
y=-2x+3


let x=0

y=-2(0)+3 and y=1-2(0)
y=3 and y=1

The lines are parallel

 

[neohashi]

hmm why the "y=3 and y=1" part? You just have to look at the coffiecients right?
y=-2x+1
y=-2x+3
-2 = -2, therefor the lines are parallel.

 

[stapel]

let x=0....
The lines are parallel

You cannot determine the slopes from the y-intercepts. To find the slopes (and thus to determine if the lines have the same slope and are thus parallel), please read and follow the instructions provided earlier.

Thank you.

Eliz.