How do I know which exact numbers to use when I plot a straight lined function?

Answer 1

Use the ones which gives you integer values of both x and y, so that it would be easier for you to solve.
For e.g. if y=(2/3)x + 3
Use x= 3 => y= 5
or use x=6 => y =7

Answer 2

y = mx + c

This is the normalised form of a linear function (a straight line).

Depending on the accuracy of your plotting (scale of graph paper, size of pencil...) you do not need to take 'exact' numbers. Any number will do.

However, it is always easier to use integers.

If m and c are integers, than any integer value of x will give an integer value of y.

If m is a rational fraction (written, let us as, as p/q where p and q are relatively prime -- i.e., a simplified fraction), then use multiples of q for x.

e.g.,

y = (7/3)x + 4

x : y
-3 -3
0 +4
3 11
6 18

If m is irrational, then it does not matter what you use for x.

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Any two points is sufficient to draw the graph (all the other points should be on the same straight line). However, if you draw as 'well' as I do, take three or four points just to make sure your line is OK.

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Of course, two useful points are where x = 0 (then y = c) and where y = 0 (then x = -c/m)

Answer 3

you look at the scale your graph has, so say in the positive x direction it is 0-20, then you would maybe plot every fifth one (0,5,10,20), with its corresponding y value, and join up the dots!

However, if you aren't given a predefined scale, then just use something easy to work with, ie 10 units in every direction on the cartesian diagram, and choose what you judge to be suitable intervals given the question, maybe every 2?

hope this helps.

Answer 4

did you want to plot a stright line then take any numbers which are belongs to integers ,rational numbers ,

Answer 5

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