Hello,

Can you please help me figure this out?

Problem: How close to -3 do we have to take x so that

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- Jan 22nd 2010, 12:57 AMl flipboi lHow close?
Hello,

Can you please help me figure this out?

Problem: How close to -3 do we have to take x so that

- Jan 22nd 2010, 01:06 AMdrumist
is non-negative, so we can just move some stuff around:

- Jan 22nd 2010, 01:24 AMl flipboi l
- Jan 22nd 2010, 01:34 AMdrumist
Say for example we considered something like . It's possible for to be a negative number, but if it was negative, the value on the left-hand side would have been negative, and a negative number can't be greater than 1000. So we just need to make a side note that we are only considering values of such that . From then we can continue the problem.

As for your second question: Any time you take an even-powered root of a value, you must take its absolute value. In other words:

Notice that had we not done so, we would not have found the solution , but clearly .

You do not need to do this when taking odd-powered roots.