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Math Problem Answered

What will be the equation for y for the following graph?

y=5, x=0
y=4, x=1
y=3, x=2
y=2, x=3
y=1, x=4
y=0, x=5

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steveastroukBest Answer (author)2013-03-05

What shape do you think its going to be ?

Take a piece of graph paper and plot it. There are of course programs that can do it, but your won't learn much that way.

Find the points at which the line intersects the axes.

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Wisaam (author)steveastrouk2013-03-05

The line intersects the 'x' axis at point (5,0) and intersects the 'y' axis at point (0,5). I have already made the graph and 'y' is inversely proportional to 'x' but I can't come up with an equation for 'y'. The graph is like straight line going from top to down.

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steveastrouk (author)Wisaam2013-03-05

RiGHT.
This is a linear function, which has the form Y=MX+C, where M is the gradient and C is the Y offset.

Set X=0 Y=C. So that you can find from the answers you have.

Now, set Y=0, and rearrange the equation to give you "M". Substitute the values you already have.

This is stuff we did when we were about 12 in the UK when I was younger.

Steve

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Wisaam (author)steveastrouk2013-03-05

Sorry I didn't understand a bit of it, what will be the value of M?

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steveastrouk (author)Wisaam2013-03-05

That's what you have to calculate from the numbers you have.
Alternatively, go away and study the equation of the straight line. Look at the maths I showed you, with the Y=MX+C Play with some numbers into it, say M=0.5, C=1, X=0...5 Repeat for M=1, 2 etc

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Wisaam (author)steveastrouk2013-03-05

Thanks a lot. It worked, but I have a question here, why can't we use proportionality here,

as y is inversely proportional to x,
so y=m/x + c

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steveastrouk (author)Wisaam2013-03-05

WELL DONE ! Great work. Now you know a little bit more about maths.
In answer to your other question:

Plot it. Y=1/X is NOT linear !

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Wisaam (author)steveastrouk2013-03-06

Here is another question. Please answer it too in an understandable way like you did here.

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steveastrouk (author)Wisaam2013-03-05

PS Don't forget to select the best answer.

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steveastrouk (author)Wisaam2013-03-05

Y=MX+C

Let Y = 0

0=MX+C

C is known. X, when Y =0 is known. Calculate M

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Kiteman (author)2013-03-05

If you find your homework difficult, you ought to talk to your teacher about it first.

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Wisaam (author)Kiteman2013-03-05

Actually it's not homework. It's not even related to any of the chapters I study in school.

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