Quick math question before my final, HELP!

Nocturnal

Lifer
Jan 8, 2002
18,927
0
76
The equation xy = 6 is not a linear equation.

True or False.

My answer sheet says it's TRUE, but how would I go about figuring this out?

Would I a) choose three points of the x and y axis and plot them to see if they work out?

b) solve for one of the variables?

c) hELP!
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
Divide both sides by x

xy/x = 6/x

y = 6/x

note that 6/x is not a straight line (it's not even defined at 0)
 

Haircut

Platinum Member
Apr 23, 2000
2,248
0
0
A linear equation can be written in the form y = mx+c

The equation you have can be rewritten as y = 6 * (x^-1) thus it is not linear.
 

xirtam

Diamond Member
Aug 25, 2001
4,693
0
0
yeah, divide by the variables, you get 6/x... so obviously it's going to be discontinuous at y=0, so you know it can't be linear since it's got a discontinuity.
 

Muse

Lifer
Jul 11, 2001
40,426
9,941
136
Get or make a piece of graph paper and plot it. You can do it in 10 minutes. It will be totally obvious to you if it's linear or not. Does the graph look like a line?
9
8
7
6 .
5
4
3 .
2 .
1 .
0 1 2 3 4 5 6 7 8 9

<---- x ---->
 

Muse

Lifer
Jul 11, 2001
40,426
9,941
136
Originally posted by: Muse
Get or make a piece of graph paper and plot it. You can do it in 10 minutes. It will be totally obvious to you if it's linear or not. Does the graph look like a line?
9
8
7
6 .
5
4
3 .
2 .
1 .
0 1 2 3 4 5 6 7 8 9

<---- x ---->

Note!! This looks OK in preview, but not as a post. To see the graph, reply to it, quoting and you can see that the curve is asymptotic to the x and y axes.

 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
49,601
167
111
www.slatebrookfarm.com
God, I love this forum... I said "asymptotically" today and no one knew what I was talking about. 2 hours later, here I am, and I run into it.
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
Originally posted by: DrPizza
God, I love this forum... I said "asymptotically" today and no one knew what I was talking about. 2 hours later, here I am, and I run into it.

I'm curious as to what type of conversation that word came up in outside of a math classroom.
 

Rainsford

Lifer
Apr 25, 2001
17,515
0
0
Originally posted by: Tyler
Originally posted by: DrPizza
God, I love this forum... I said "asymptotically" today and no one knew what I was talking about. 2 hours later, here I am, and I run into it.

I'm curious as to what type of conversation that word came up in outside of a math classroom.

He got closer and closer to a girl, but never actually got her? :p