Can you just cancel the variable of this equation?

2010-05-01 11:52 pm
yz>-yz, can you cancel out z? No right? Because you don't know the sign of the variable?

回答 (3)

2010-05-02 12:11 am
Let x = yz, x will just be some number, could be positive or negative.

Plug x into equation:
x > -x

If you think about this for a minute it can only be true when x is positive.

If x is positive then x will definitely be larger than its negative counterpart.

If x is negative the inequality says that a negative number is greater than -1 times that negative, which will be positive. But a negative cant be bigger than a positive.

So x > 0, or yz > 0.
2010-05-01 11:56 pm
If its a variable, you're not supposed to ever cancel it.
If you treat it as a constant, then I suppose you could cancel it out.
2010-05-01 11:55 pm
well a varible is also 1 so u can make the equation more like yz>-yz
-z -z
y>(-z squared)

that u subract on both ends but because its a negative its more added making in squared


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