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June 26th, 2011, 11:29 PM   #1
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why the product of two negative integers is positive

because the multiplication operation is a repeated addition operation

for example

(-3) x (-2) = - ( 3 x -2 ) = - ( (-2) + (-2) + (-2) ) = - (- 6 ) = 6 and 6 is positive integer

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June 26th, 2011, 11:34 PM   #2
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Let a be positive and b be negative. ab < 0 is correct. Since -a is negative, multiplying both sides of the inequality by -1 gives -ab > 0.
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June 26th, 2011, 11:49 PM   #3
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Re: why the product of two negative integers is positive

yes johnny
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June 27th, 2011, 02:23 AM   #4
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Re: why the product of two negative integers is positive

1 = (1)(1)

1 = (1)(1) + 0

1 = (1)(1) + 0(-1)

1 = (1)(1) + (1 - 1)(-1)

1 = (1)(1) + (1)(-1) + (-1)(-1)

1 = (1)(1 - 1) + (-1)(-1)

1 = (1)(0) + (-1)(-1)

1 = (-1)(-1)
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June 27th, 2011, 02:46 AM   #5
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Re: why the product of two negative integers is positive

then by your assumption:

(-3)*2=-6
(-3)*(-2)=-6

2=-2 ???
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June 27th, 2011, 11:02 AM   #6
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Re: why the product of two negative integers is positive

We can carry out the experiment. Take a piece of paper - it will be our first plane. Draw a line from north to south, this we will create two planes-western and eastern (- and +).All with the sign (-) is the property of western plane , sign (+) means that all it belong to east plane. Now draw the same squares in each plane and find their area. If you use negative values ??of length and width in the western plane you get ONLY plus value areas- but this is wrong (in our case)!!!
Why is this not correct? Because the plus value of the area, are the property east of the plane. One value of length or width should be (-) and one (+) in western plane. My thoughts ...
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June 27th, 2011, 02:45 PM   #7
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Re: why the product of two negative integers is positive

it is really wonderful job
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June 28th, 2011, 05:22 PM   #8
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Quote:
Originally Posted by filipd
by your assumption
What assumption?
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