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## #1 2005-10-06 08:00:06

the stuck guy
Guest

### help plz

i have a question infront of be that reads" write down the gradient and y-intercept for each of these straight lines" then it says "b)      2y = 4x - 12 " i know how to set up the table but why is there a 2y what do i do when i am trying to find the co-ordinates like x|0|1|2|3|4|5|
y|?

## #2 2005-10-06 10:09:56

MathsIsFun
Registered: 2005-01-21
Posts: 7,685

### Re: help plz

Straight lines are usually written in the form:

y = mx + b

So, you can change your equation to suit:

Divide by 2: y = 2x - 6

Then for any x you can calculate y, for example: if x=4, then y = 2 × 4 - 6 = 8-6 = 2

And you can see that the gradient is 2 (because y changes by 2 when x changes by 1)

And the y intercept is when x=0, so: y=2x-6= 2 × 0 - 6 = -6

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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## #3 2005-10-06 16:13:35

ganesh
Registered: 2005-06-28
Posts: 24,639

### Re: help plz

In India,
y = mx + c
where c is the y intercept and -x/y is the slope (or gradient),
when written as y - mx - c = 0

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #4 2005-10-06 18:01:08

MathsIsFun
Registered: 2005-01-21
Posts: 7,685

### Re: help plz

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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## #5 2005-10-06 20:39:22

ganesh
Registered: 2005-06-28
Posts: 24,639

### Re: help plz

Yes, very much British

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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