Confuse about one formula?

Indonesia
March 6, 2007 12:19am CST
i would like to ask a question, if 1 x 2 = 2, i think that it's make sense. and 1 x -2 = -2, i think that it's make sense, but if -1 x -2 = 2. so hard for me to explain the logic. DO you have the logic to explaino r solve this problem? thank you
4 responses
astaha
@astaha (129)
• India
27 Oct 07
same as friend of ur friend is ur friend enemy of ur freind as well as friend of ur enemy is ur enemy and enemy of ur enemy is ur friend at least in that respect
astaha
@astaha (129)
• India
27 Oct 07
(ofcourse)if u consider positive as ur friend and negative as ur enemy
coolcat123
@coolcat123 (4387)
• India
28 Dec 08
We have been taught that minus minus cancels each other so we go on that and don't think further. You would surely get an explanation by finding on such books.
RAMPersona
@RAMPersona (2033)
• Philippines
11 Mar 07
from a formal viewpoint, multiplication between two negative numbers is directly received by means of the distributive property, example: (just to prove) (-1) x (-1) = (-1) x (-1) + (-2) + 2 = (-1) x (-1) + (-1) x 2 + 2 = (-1) x (-1 + 2) + 2 = (-1) x 1 + 2 = (-1) + 2 = 1
lotabi
@lotabi (22)
• United States
6 Mar 07
Think of this vectorially. Imagine positive (+) as going in a certain direction. Then: 1 X 2 = 2 means going in that direction by a certain amount 1 x -2 = -2 means going in the opposite direction by the same amount -1 x -2 = 2 means going in the opposite of the opposite direction by the same amount (i.e. opposite of opposite brings you back to the same direction as the first case!). Hope this helps!