# Key to Algebra- annoyed

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So, the answer key for Key to Algebra is annoying me. Has anyone else used this and found errors? I am not great at Algebra to begin with and I need the key to be right!!

When multiplying integers - the rule is postive x negative = negative right? Also, negative x negative = positive right? So the key says

(-3)(-3)(-3) = -27 but it shoud be +27 right? Am I right or am I missing something?

Another one says 6 x -5 x -3 = 90 but shouldn't it be -90 ???

My son doesn't need this confusion!:banghead:

Edited to add: OK- nevermind. I have had my coffee and I see clearly now. It's just another moron morning over here!!

Edited by TXMary2
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So, the answer key for Key to Algebra is annoying me. Has anyone else used this and found errors? I am not great at Algebra to begin with and I need the key to be right!!

When multiplying integers - the rule is postive x negative = negative right? Also, negative x negative = positive right? So the key says

(-3)(-3)(-3) = -27 but it shoud be +27 right? Am I right or am I missing something?

Another one says 6 x -5 x -3 = 90 but shouldn't it be -90 ???

My son doesn't need this confusion!:banghead:

(-3)(-3) is positive. 3. Then that(3)(-3) is negative. So the answer is -27.

(6)(-5) is (-11). That (-30)(-3) will result in a positive. 90.

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(-3)(-3)(-3) the first 2 are multiplied to get a positive 9-- now you have (+9)(-3) and positive times a negative is a negative so result is -27

For the second one :6 x -5 x -3

6 x (-5) = -30

(-30) x (-3) = + 90 negative times a negative is a positive.

You can only multiply 2 numbers together at one time when you have 'strings' of multiplication. Both of your problems require 2 steps.

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the rule is postive x negative = negative right? Also, negative x negative = positive right

If that is so, then -3times-3 would equal +9. +9times-3 would equal -27.

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No, the answers in the book are correct.

Your statement above is correct too. A negative times a negative is a positive. And a negative times a positive is a negative. But a negative times a negative times a negative is a negative... ;)

An odd number of negative multipliers will give you a negative number.

And even number of negative multipliers will give you a positive number.

Think about it in words, if that helps. I like Sarah Lee is positive. I don't like Sarah Lee is negative. "Nobody doesn't like Sarah Lee" (the old ad campaign) is positive -- it means that *everybody* likes Sarah Lee. But if "It's not true that nobody doesn't like Sarah Lee," takes you back to a single negative: somebody doesn't like Sarah Lee. But if you said, "It's not untrue that nobody doesn't like Sarah Lee," then once again the ultimate *meaning* of your statement is positive: everybody likes Sarah Lee... It goes on and on forever. Two negatives cancel each other out. A third makes the whole negative again. Odd numbers of negatives = a negative.

And a trick for this? Just imagine two subtraction symbols ganging up to make an addition symbol. :)

So if you have: (-5)(-3)(-2)(-7)(-2)= (+5)(3)(+2)(7)(-2)= (5)(3)(2)(7)(-2)= -420...

But if you have:(-5)(-3)(-2)(-7)(-2)(-1)= (+5)(3)(+2)(7)(+2)(1)= (5)(3)(2)(7)(2)(1)= 420...

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:banghead::banghead: UGH! OK- I see that now. Thank you. I think I will go have my coffee now.

Edited by TXMary2
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Just wanted to say that you made my day by asking an algebra question I can actually answer! LOL

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Just wanted to say that you made my day by asking an algebra question I can actually answer! LOL

Gee, glad I could help. :tongue_smilie: LOL

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