can someone prove dat (-1)*(-1)=1?

Question

by proof i mean mathemaically proving using logical assumptions just like a

Answer 1

multiply is a form of addition means if we say 2*2 means add 2, e times, means 2+2. same if u say 2*1 then it means add two one time that is 2, if u say 2*0 that means add 2, 0 times that don't add.
if we say 2*-1 that means u r adding 2 once but in rever direction that means u move to ther left and reach at -2.
in case of -1*-1 u try to add -1 once but u move in reverse so u move to right in place of left and u reach at +1

and if u think u got a stupid ans then i should say u ask a stupid one so u did negative i did too but the result is positive, lol

Answer 2

i find the best proof for this is to do it graphically, as most people are happy with a set of axes ( x & y ) with x postive to the right and negative to the left, and correspondingly y positive up and negative down from the origin.
Most people are happy that for a cuboid, length times width equals area. So you can move up +1 on the x axis and +1 on the y axis and form a square. Then you show that for a (+1) x (+1) square the area covered would be +1 unit. Do the same now but move up in the negative direction. This is the same size unit of area for the (-1) x (-1) square.
This is actually more convincing if you use other -ve numbers other than 1 as people sometimes get mixed up over 1's special properties. So by proving that the area for a 3 x 4 rectangle is the same ( and therefore cannot be negative ) as a ( -3 ) x ( -4 ) rectangle

Answer 3

Suppose that:
#1: a*(b+1)=a*b+a
#2: a*1=a
This is justified as a definition of multiplication, since you define multiplication of a by b as adding a b times, and clearly if you add a (b+1) times, you will have a more than if you only added it b times. a*1=a is also basic. Then:

-1*1=-1 by #1
-1=(-1)*(0+1)=(-1)*0 + (-1) by #2, also using 0+x=x
0=(-1)*0 by adding 1 to both sides, note that -1+1=0, so the -1 on the right cancels.
0=-1*(-1+1)=(-1)*(-1) + -1 by #2, also using -1+1=0
1=(-1)*(-1) by adding 1 to both sides
(-1)*(-1)=1 by symmetry of equality
Q.E.D.

Answer 4

Multiplying any number by -1 gives the opposite of that number.

The opposite of negative 1 is positive 1. So (-1) * (-1) = the opposite of -1, which is +1.

E-mail me if you want the full version - I can also do this in as much detail as you want.

Answer 5

The basic rule of multiplication states
"when a negative integer is multiplied with another negative integer the product is an even integer"
Therefore (-1)*(-1)=1

Answer 6

Take a calculator and do the calculation. Since the calculator says 1. the answer must be 1 because calculators never lie.

Answer 7

i think it is a fact that when 2 negatives multiply, result is a positive number. so, i don't think there is a possible explantation for your question with the help of assumptions.

Answer 8

can you proof that 2=2 ?

Answer 9

I have already proved kindly refer to

Answer 10

a negative multiplied by a negative gives us a positive answer.
eg: (-x) *(-x)= x