Question

I really need help with Linear Equations. I dont understand how someone can turn y=1/2x-5 into coordinates to go on a plane... That question above is just an example. I need some help understanding how to do this please.

Answer 1

I need to understand your plight first... you need points to plot on the plane? ^_^

Answer 2

\[ y = \frac{1}{2} x -5 \]?

Answer 3

Yes in my lesson it is somehow adding points to that on a table?

Answer 4

Well, if you're just looking for points, then the first step here is to just pick a value for x. Any value should work, but for simplicity, I recommend you pick even numbered values...

Answer 5

the equation tells you (if you know how to interpret it) how to find a y value for a given x value.... the idea that for every x there is a special y that goes with that x

Answer 6

So it can just be random? How is that math???

Answer 7

You're looking at it the wrong way :)
There are infinitely many points that would satisfy your equation, you certainly can't name them all.
However, you can determine SOME points by picking a few values for x and determining the EXACT values of y that go with each respective x-value :P

Answer 8

to find the y that goes with x=0 (for example) replace x in the equation with the number 0
y = (1/2)*0 - 5
and simplify.

1/2 times 0 is 0, so this is
y = 0-5
and 0-5 is -5

all of that says that the pair (0,-5) go together

Answer 9

yes, they are showing you how to do it.

Can you do each of the steps ?

Answer 10

Every thing but putting it into a table.

Answer 11

Well, the points under the x-column were rather random too, chosen by whomever wrote that table... you can make your own table :)

Answer 12

So i just pick a random x or a random y and work out the problem?

Answer 13

the table is x and y
in the x column you put x
in the y column you figure out the y using that x

Answer 14

You can pick a random x OR a random y-value, but not both.

It's highly recommended that you pick x at random, as picking a random y-value would involve extra work at solving for x...(not by much though)

Answer 15

you would pick an x (because if you pick the y, it will be hard to figure out the x unless you do algebra)

Answer 16

lol, and as you can see, under the x-column, only even-number values were picked for x :P

Answer 17

Ok i understand now. So if i was to do y=2x-10 I would pick my x y=2 * 5 - 10 and solve for y?

Answer 18

Yup :)

Answer 19

Ok TY guys so much i had no clue what i was doing XD!!!

Answer 20

And you'll find that no matter what values you pick for x, they will all lie on the same line if you graph ^_^

Answer 21

Here is an example of this problem as a short video
http://www.khanacademy.org/math/algebra/linear-equations-and-inequalitie/graphing_solutions2/v/plotting--x-y--relationships

Answer 22

Oh Thank you i forgot about khanacademy