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If x^2-2xy=84 and x-y=-10, what is the value of |y|?

Question

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If x^2-2xy=84 and x-y=-10, what is the value of |y|?

anonymous · Answer

just answer the problem with steps

abb0t · Answer

But anyways, what you're going to want to do here is use substitution. You can rearrange x-y=-10 
to 
x = -10 + y 

plug it into the other equation to solve for "x" 
and then solve for "y".

abb0t · Answer

Can you try that.

anonymous · Answer

Is there another way? That's way too long according to my solution

nincompoop · Answer

all of them will end up having to  solve for y

anonymous · Answer

Whats another way?

anonymous · Answer

I need to do problems like this in less than 2 minutes i'm preparing for the GRE

nincompoop · Answer

ya that is quicker than 2 minutes

nincompoop · Answer

you can solve the first one mentally and that is like 5 seconds

abb0t · Answer

Ah, the GRE. Gotcha. They usually don't involve long processes. But subsitution method is the best method I can suggest.
You can try to use elimination method as well, but, that might be difficult, since you have 
x-xy together.

anonymous · Answer

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