Math Is Fun Forum

mom

Member

Registered: 2012-04-25

Posts: 94

equation of a parallel line

I am stumped again.

Find the equation of line L in standard form. L is parallel to y=1/3x.
I am not sure why I am thrown off. It shows line L with a point of (2,4)

I have y=-x+6 and I know that can't be correct because the slopw is 1/3 so is it y=-1/3x+6
I am really confused.
Please help to see what the answer is and why so that I can understand.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,803

Re: equation of a parallel line

hi Mom,

To be parallel it must have the same gradient, ie. 1/3

So y = (1/3)x + something..

(2,4) => 4 = (1/3)2 + something => something = 4 - 2/3

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: equation of a parallel line

Well, we know that it must be of the form y=1/3 x+n, so we just substitute x=2 and y=4 and solve for n. Can you do that?

Last edited by anonimnystefy (2013-05-08 06:59:03)

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

mom

Member

Registered: 2012-04-25

Posts: 94

Re: equation of a parallel line

Im still lost but thanks Bob

Bob

Administrator

Registered: 2010-06-20

Posts: 10,803

Re: equation of a parallel line

http://www.mathsisfun.com/equation_of_line.html

and

http://www.mathsisfun.com/data/straight_line_graph.html

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

stapel

Member

Registered: 2006-07-22

Posts: 15

Re: equation of a parallel line

Im still lost but thanks Bob

On which part are you lost? Thank you!

johnnie too lazy log in

Guest

Re: equation of a parallel line

simple, just note that it goes thru (0,0), so subtract from y and and x the 2 and the 4.
(y-4) = (1/3)(x-2)
that's all there is to it.
very simple.
the end.
lol.