why is a negative x a negative a positive ?

Question

can't find an answer from any of his teachers even those who teach higher math .

Answer 1

i think its like how in the english lkanguage a double negative would make it positive, like saying im not not going to my room is the same as saying im going to my room, the second negative contracts the first and eliminated the negative altogether

Answer 2

The following is from Dr. Math. It's about the best explanation I've seen.

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Debt is a good example of a negative number. One common form of debt is a mortgage in which you owe the bank money because the bank paid for your house. It is also common for an employer to deduct a mortgage payment from an employee's paycheck to help the employee keep on schedule with the payments.

Suppose $700 is being deducted each month to pay the mortgage. After six months, how much money has been taken out of the pay for the mortgage? We can figure out the answer by doing multiplication.

6 * -$700 = -$4,200

This is an illustration of a positive times a negative resulting in a negative.

Now suppose that, as a bonus, the employer decides to pay the mortgage for one year. The employer removes the mortgage deduction from the monthly paychecks. How much money is gained by the employee in our example? We can represent "removes" by a negative number and figure out the answer by multiplying.

-12 * -$700 = $8,400

This is an illustration of a negative times a negative resulting in a positive.

If one thinks of multiplication as grouping, then we have made a positive group by taking away a negative number twelve times.

Answer 3

Hmmm... I think I can help you here. Though it will be hard to prove without pictures. I will try my best to help you - I learned this about 3 years ago, so it might not be well explained. This is how IMP taught it to me.

Say that you had a magic cauldron (I know, just go with it!) in which to bring up the temperature of it you have to use special cubes. Hot cubes ( I will use X for pictorials) represent positive 1 degree each, while Cold cubes (I will use O for pictorials) represent negative 1 degree each.

Say that you have 12 hot cubes and 12 cold cubes in the cauldron. Because a hot cube and cold cube cancel out each other, the temperature is 0 degrees.

XXXXOOOO
XXXXOOOO
XXXXOOOO


One way to raise the temperature is to take out cubes. Say that the dish you are going to make calls for the cauldron to be positive 12 degrees. So say you are going to take out 3 bunches of 4 cold cubes. Mathematically, that would be written:

-3 x -4

because you are taking out 3 bunches, making the 3 negative and in each bunch, there are 4 cold cubes (cold cubes are negative 1 each).

Now that they are taken away, that leaves 12 hot cubes in the cauldron.

XXXX
XXXX
XXXX

Therefore, the temperature is +12 degrees.

So, -3 x -4 = 12.

I hope that helps you. If not, I'm sorry. :(

Answer 4

The mathematical experts have done a lot of research, and all our calculation are correct so why bother. Just think if a sentence has 2 negative it becomes positive.

Answer 5

I explained it to my sister like this: "Suppose you had -1 boxes with -1 apples in each...".

Consider 3x3 = 9, 2x3 = 6, 1x3 = 3, 0x3 = 0, -1x3 = -3, -2x3 = -6, -3x3 = -9. Each time, the result goes down by 3.

Now consider -3x3 = -9, -3x2 = -6, -3x1 = -3, -3x0 = 0, -3x-1 = 3, -3x-2 = 6, -3x-3 = 9. Each time the result goes up by 3.

Answer 6

Let's say you walk from your home to your school and we call that a positive direction.

Now, if I ask you to "change direction, 180 degrees", that is the same as multiplying by a negative number, say -1.

In our example above, it means you have to turnaround and walk back to your house.

Now, if I were to multiply by another negative number, say -1, again, it means you have to turn around again.

So, now, after turning around twice, you will be walking to school once more and you are in the positive direction.

Remember, multiplying by -1 is to reverse a direction.

Another example, I owe you $10. If we were to reverse direction, it means you owe me $10.

$10 x -1 = -$10 (this means you have less $10, since you owe me the money.

If we do that once again, you will get back your $10,

-$10 x -1 = $10

Hence, -1 x -1 = 1.

In Summary.

Face School
Face Home (change direction)
Face School (change direction again)

I owe you
You owe me (change direction)
I owe you (change direction again)

Hope that helps

Answer 7

A negative is just fancy-talk for "opposite".

[-1*-1] is the same as opposite of -1. Which is 1.

Answer 8

Well, two negatives cancel each other out. Thus, it becomes positive. But two positives don't cancel each other.

Answer 9

if x is -5 then x= -5 right? add a negative to each side then -x = -(-5) makes 5

Is that it?

Answer 10

- is a negative
+ is a positive
-x is negative x
+ is positive x

is that what u mean?