exponents — homework help?

Could someone please explain to me why -5^2 = -25

while (-5)^2 = 25 ?

In other words, why does a negative number in parenthesis raised to an even power equal a positive number but when a negative number isn’t in parenthesis being raised to an even power its negative?

and I’m also wondering, is it true that any number raised to an even power is positive?

thanks

Top 2 Answers

A few days ago

Anonymous

Favorite Answer

The first equation, -5^2= -25, is being read by your calculator as

-(5^2)= -(25) = -25

It does whatever is in parentheses first, then it does the negative sign next.

The second equation, (-5)^2=25, is being read by your calculator as

(-5)^2=(-5*-5)=25

Same process there, it does whatever is in parentheses first.

To avoid ambiguity, always use parentheses.

A few days ago

fcas80

I think the trick is to be careful how you use parentheses.

-(5^2) = -25

Yes, any number raised to an even power is positive.

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exponents — homework help?

exponents — homework help?

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