# Linear equations in two variables add. help

• May 26th 2008, 07:08 AM
rowdy3
Linear equations in two variables add. help
Two points are given from each of two lines. Without graphing the points, determine wheather the lines are parallel, perpendicular or neither.
Line 1: (4, -6) (3, -2)
Line 2: (3, -1) (7, 0)
This is what I did.
-2 - (-6) = 4
3- 4 = -1

0 - (-1) = -1
7 - 3 = 4
Would it be perpendicular?

Write the slope-intercept form of each line. Then determine wheather the graphs of the lines are parallel, perpendicular, or neither.
4x + 2y = 8
2x + y = 1
This is what I did
4x + 2y = 8 / 2
y = -2x + 1
slope-intercept form: y= -2x + 4
slope-intercept form: y= -2x + 1
Is it parallel?
Thanks
• May 26th 2008, 07:12 AM
masters
Quote:

Originally Posted by rowdy3
Two points are given from each of two lines. Without graphing the points, determine wheather the lines are parallel, perpendicular or neither.
Line 1: (4, -6) (3, -2)
Line 2: (3, -1) (7, 0)
This is what I did.
-2 - (-6) = 4
3- 4 = -1

0 - (-1) = -1 ==== should be +1
7 - 3 = 4
Would it be perpendicular?

Responding to your first question, you made a mistake on the slope for line 2.
Should be 1/4. So the lines are perpendicular.
• May 26th 2008, 07:14 AM
masters
Quote:

Originally Posted by rowdy3
Write the slope-intercept form of each line. Then determine wheather the graphs of the lines are parallel, perpendicular, or neither.
4x + 2y = 8
2x + y = 1
This is what I did
4x + 2y = 8 / 2
y = -2x + 1
slope-intercept form: y= -2x + 4
slope-intercept form: y= -2x + 1
Is it parallel?
Thanks

You are correct. Slopes are the same (-2) so the lines are parallel