SOLUTION: for each pair of equations, determine if the lines are parallel, perpendicular, or neither. y-3x=10 and 3y+x = -5 I have no idea how to start. Thank you.

Algebra ->  Linear-equations -> SOLUTION: for each pair of equations, determine if the lines are parallel, perpendicular, or neither. y-3x=10 and 3y+x = -5 I have no idea how to start. Thank you.      Log On


   



Question 76628: for each pair of equations, determine if the lines are parallel, perpendicular, or neither.
y-3x=10 and 3y+x = -5
I have no idea how to start. Thank you.

Found 2 solutions by Earlsdon, josmiceli:
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Determine whether the lines are parallel, perpendicular, or neither.
1) y+-+3x+=+10 and
2) 3y+%2B+x+=+-5
First, put your equations into the slope-intercept form: y = mx + b
1) y+=+3x+%2B+10 and
2) y+=+%28-1%2F3%29x+-+5%2F3
Notice that the slope (m) in equation 1) is 3 and the slope (m) in equation 2 is -1/3
Recall that perpendicular lines have slopes that are the negative reciprocal of each other.
So, equation 1) has a slope of 3 while equation 2) has a slope of -1/3 which is the negative reciprocal of 3. The lines are, therefore, perpendicular.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
All you care about is the slopes of the lines.
If the slopes are equal, they are parallel.
If they are perpendicular, they have the relationship
m%5B1%5D+=+-+1%2Fm%5B2%5D
First, find the slopes
y+-+3x+=+10
add 3x to both sides
y+=+3x+%2B+10
The form is y+=+mx+%2B+b where m is the slope, so m%5B1%5D+=+3
-----------------------
3y+%2B+x+=+-5
subtract x from both sides
3y+=+-x+-+5
divide both sides by 3
y+=+-%281%2F3%29x+-+5
so, m%5B2%5D+=+-%281%2F3%29
The relation m%5B1%5D+=+-+1%2Fm%5B2%5D is true, so the lines
are perpendicular. All you care about is the numbers in
front of the x.