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# Line Tweet

Maths and statistics discussion, revision, exam and homework help.

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1. Line
How would I draw the line
x+2y=8
2. Re: Line
Find out where it cuts the x and y axis first, plot those points. You could then find a point for a large x and small x value, plot those, and join them all up?
3. Re: Line
(Original post by flown_muse)
Find out where it cuts the x and y axis first, plot those points. You could then find a point for a large x and small x value, plot those, and join them all up?
How would I do that?
4. Re: Line
(Original post by zed963)
How would I draw the line
x+2y=8
x+2y=8
2y=-x+8
y=-0.5x+4

Cuts the Y axis at 4
Has gradient -0.5

Put in random values of X and plot the points, then draw the line across the points.
5. Re: Line
(Original post by stupefy!)
x+2y=8
2y=-x+8
y=-0.5x+4

Cuts the Y axis at 4
Has gradient -0.5

Put in random values of X and plot the points, then draw the line across the points.
Thanks
6. Re: Line
(Original post by stupefy!)
x+2y=8
2y=-x+8
y=-0.5x+4

Cuts the Y axis at 4
Has gradient -0.5

Put in random values of X and plot the points, then draw the line across the points.
You shouldn't have done that. He'll never learn if you just give him the answer. Also, if you'd read the info about the forum you would see we're not allowed to give the full answer, you have to give them hints towards it.
7. Re: Line
(Original post by flown_muse)
You shouldn't have done that. He'll never learn if you just give him the answer. Also, if you'd read the info about the forum you would see we're not allowed to give the full answer, you have to give them hints towards it.
You should have just said rearrange the equation into the form y=mx+c

but you didn't say it clearly therefore I was a bit confused.
8. Re: Line
(Original post by zed963)
You should have just said rearrange the equation into the form y=mx+c

but you didn't say it clearly therefore I was a bit confused.
You don't really need to do that. The point where it cuts the x axis is when y = 0, so you sub y = 0 and find the value of x. The point where it cuts the y axis is when x = 0 so sub that in and find the value of y.

It's a straight line so no more points are needed - just join those two up and extrapolate.
9. Re: Line
(Original post by zed963)
You should have just said rearrange the equation into the form y=mx+c

but you didn't say it clearly therefore I was a bit confused.
Well, he didn't say that either. And it doesn't need to changed into y=mx+c for you to be able to draw the line.
10. Re: Line
(Original post by zed963)
How would I draw the line
x+2y=8
You only need to find two points to draw a straight line so you don't really need to use y=mx+c here. Just plug in two x values e.g.

x=0 -> 2y=8 -> y=4
x=2 -> 2y=6 -> y=3

So you have two points on the line: (0,4) and (2,3).

Edit: Too late!
11. Re: Line
The second part of the question is

Use the graphs to find estimates for the solution of
x + 2y = 8
y=x/2-1

How would I do this
12. Re: Line
(Original post by zed963)
The second part of the question is

Use the graphs to find estimates for the solution of
x + 2y = 8
y=x/2-1

How would I do this
You will also need to draw the line y=x/2 - 1 on the same axes. The point where the two lines intersect will be the solution of the simultaneous equations.
13. Re: Line
(Original post by notnek)
You will also need to draw the line y=x/2 - 1 on the same axes. The point where the two lines intersect will be the solution of the simultaneous equations.
x=5 and y=1.5

Hmm wasn't so hard after all.
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