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colbtech
Aug 1, 2005, 04:33 AM
I have been asked this poser by a "friend"...

X, Y, and Z satisfy:
X - Y - Z = 0 and 2X + Y + 3Z = 0
If Z is nonzero, what is the ratio of X to Z?

I'm not sure I understand what is required.. is this a simple linear equation?

As in z = -1.5x?

It seems a little obvious, but...

Please help, my O level in maths was many years ago.

Colin

CroCivic91
Aug 1, 2005, 02:53 PM
Let's call X - Y - Z = 0 formula number 1 and 2X + Y + 3Z = 0 formula number 2.

From formula 1 we get:
y = x - z

From formula 2 we get:
y = -2x - 3z

since y = y we get
x - z = -2x - 3z
which means that
3x = -2z

Since Z is nonzero, we can divide by Z to get
x/z = - 2/3