Question 30468: First, I'm told that -X can be read as -1*X where the 1 is not written because it is "understood" and when X=9, -x= -1* +9 or -9. It would also follow that if X=-9 then -X=-1*-9 or +9.
I'm also told that a negetive number times a negetive number yeilds a positive answer. I know that 6^2=36 so it makes sense that
-6^2 would mean -6*-6 or +36.
My problem is that when I enter -6^2 into my graphing calculator, I get -36. When I enter it into my scientific calculator I get +36. A teacher explained that I should read -6 like I read -X, as -1*+6^2= -36. Another teacher explained that -6^2 means (-6)*(-6)and that the answer is infact +36. Which teacher and which calculator is right?
Found 3 solutions by mbarugel, sdmmadam@yahoo.com, Earlsdon:
Answer by mbarugel(146)   (Show Source):
You can put this solution on YOUR website! This problem is due just to the order in which you apply the operators ^ and -.
It's true that a negative number times a negative number yields a positive number, so (-6)*(-6) = 36.
However, when you say -6^2, you could either mean "find the square of -6" or "find the square of 6 and then multiply it by -1". Clearly, these two interpretationes yield different results: the first one is 36; the 2nd one is -36.
Your graphing calculator processes first the square and the minus, so the result is -36 (the 2nd interpretation). In your scientific calculator, you're telling it to take -6 and multiply it by -6. The result of this is clearly 36.
This problem is solved by correctly applying parenthesis. If you want to say "-6 squared" you should write (-6)^2. However, if you want to find the square of 6 and multiply it by -1, then you could write -(6^2) in order to avoid confusion.
Answer by sdmmadam@yahoo.com(530) (Show Source):
You can put this solution on YOUR website! Your understanding of the concept of multiplication
between real numbers is correct.
Two quantities of the same sign when multiplied give positive sign and
two quantities of opposite signs when multiplied give negative sign
Since (+6)*(+6) and which we usually express as 6*6 = 36
and also (-6)*(-6) = 36
when we find the square root of 36 we say +6 or -6
Normally if you write -6^2 it means (-1)multiplied by (6*6) = (-1)*(36) =-36
And (-6)*(-6) means (-6)whole squared
which we express as (-6)^2 = (-6)*(-6) = 36
All math teachers would convey the same thing to you.
Different calculators have different modes of commands.
You will have to please follow the manual and carry out the commands.
Your graphing calculator has understood your command -6^2 as -(6^2) = -36
If you wish it to give you +36 you must give a suitable command
that actually means (-6)^2
I hope I have made myself understood.
Answer by Earlsdon(6294) (Show Source):
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