What do u think -1 x -1 is = to? -1 or 1? It says in text books its 1 but I'd lyk to know other people think

Question

Some scientists believe its -1

Answer 1

The answer is 1. However, this is a point which has turned quite a few people off of maths, because it does seem counter intuitive, and it's worth taking a while to try and figure out why -1x-1=1.

I was reading about this issue somewhere (although unfortunately I can't remember where), and it gave an analogy about bank fines of £50 (with a fine being taken out of your account, and hence represented as -£50).

1x£50 bank fine=£50 taken out of your account= -£50.
2x£50 bank fine=£100 taken out of your account= -£100, etc.
-1x£50 bank fine=£50 not being taken out of your account, i.e. £50 remaining in your account = £50.

Hence, in this case, you can sort of "see" why a minus times a minus is a plus.

Mathematicians, however, don't usually appeal to this intuitive approach. To have -1x-1= -1 would contradict one of the axioms of the real numbers (an axiom is an assumption that the mathematician assumes to be true, and using only the axioms, defintions, and valid methods of proof, goes on to prove different statements). The axiom that guarantees that -1x-1=1 is as follows: for any real number p that is not equal to 0, px(1/p)=1. For you know that -1 is not equal to 0. Hence, 1/(-1) exists and is -1. But then by the axiom, -1x-1=1.

I hope that this helps

Answer 2

1

Answer 3

Got it !!!!

One way of understanding this is to regard multiplication by a positive number as repeated addition.

Thus, 2 × 3 = 2 + 2 + 2 = 6
and so naturally

(−2) × 3 = (−2) + (−2) + (−2) = −6

(−4) × (−3) = − (−4) − (−4) − (−4)
= 4 + 4 + 4
= 12

However, from a formal viewpoint, multiplication between two negative numbers is directly received by means of the distributivity of multiplication over addition:

(−1) × (−1)
= (−1) × (−1) + (−2) + 2
= (−1) × (−1) + (−1) × 2 + 2
= (−1) × (−1 + 2) + 2
= (−1) × 1 + 2
= (−1) + 2

therefore =1

however I have to confess it's something i never though of before and in the process of working it out it seems
-1 x -1 = is still equal to -1 x -1. It first seems the rule that make it = 1(+ve) comes from the result obtian from the other integers. Which is more of a scientific assumtion than an absolute analysis.

I'm still thinking

Answer 4

It is 1.

Answer 5

ITS 1

Answer 6

The text books are correct. Whenever you multiple 2 negative numbers, you get a positive answer. Think of it this way: The negative sign has 1 line, the positive sign has 2. 2 negatives gives you 1+1=2 lines which is a plus sign. Not really a valid proof, but it may help you remember.

Answer 7

As you have seen the answer is +1.

Think of multiplication like this.

Measure out the first number along the number line starting at the zero. This takes us to +1.

Carry on measuring along the line until you have done this the same number of times as the second number. In this case we only have to do this once so we are still at +1. (Try with larger numbers if this is not clear)

Now rotate the whole number line around the zero point by 180 degrees for every minus sign. As there are two minus signs here this must be done twice. The first time takes the answer to -1 (which would be the answer to +1 * -1) and the second time brings it back to +1.

Answer 8

1*1 is 1 & -*- is + so -1*-1 is 1

Answer 9

it's 1, (-1)^2 = -1 x -1.
the only time you get -1 is when u have some thing like this
-(1)^2.

Answer 10

1/2 times 1/2 =1/4
1 times 1/2 =1/2
1 times 1= 1
and so on.