Homework Help: 8th Grade Math

Posted by Sarah on Thursday, September 24, 2009 at 7:49pm.

If x/y=4, x-y=9, and y-x=-9, what is x & y?

8th Grade Math - MathMate, Thursday, September 24, 2009 at 9:08pm
x/y=4, means x=4y
substitute 4y for x in x-y=9
to get
(4y)-y = 9

Can you continue?

Note: the third equation (y-x)=-9 can be derived from the second (x-y)=9, so it gives no new information.
8th Grade Math - yves, Monday, January 3, 2011 at 7:06pm
3y

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8th Grade Math - If x/y=4, x-y=9, and y-x=(-9) then what is x and y?

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