CHAT So, a question on negative numbers

FaithfulSkeptic

FaithfulSkeptic

Carrying the mantle of doubt
Here's another for you folks.

Lets say: b = a
multiply both by a, and you get: ba = a^2
subtract b^2: ba - b^2 = a^2 - b^2
factor: b(a-b) = (a+b)(a-b)
divide both sides by (a-b): b = (a+b)
since a = b (first statement): b = b+b
or
1 = 2
 
hunybee

hunybee

Veteran Member
serveimage
 
mzkitty

mzkitty

I give up.
Dennis Olson said:
Indeed.

WHY?
Click to expand...
Bps1691 said:
With the standard number line centered at zero

… numbers on the right side of zero are positive and numbers on the left are negative

Moving a certain number of steps a certain number of times, multiplication problems are modeled

Multiplying two negative numbers together is analogous to facing the left direction, but taking steps backwards.

This movement results in a final answer that is positive.
Click to expand...

Well, that makes sense to me in a weird way.
 
Squib

Squib

Veteran Member
If you subtract all the even numbers in an infinite list of numbers, do you still have infinite amount of numbers?

1,2,3,4,5,6,7,8,9...

1,3,5,7,9...

Yes...even though you “subtracted” an equal amount of numbers!
 
W

willowlady

Veteran Member
"But the point is a made up construct because you can't really see or feel A Point in space. " The key to the answer is that math is a CONSTRUCT to attempt to describe reality. I do not know the answer you seek, but the next time I get my grandkids' math blocks out, I shall attempt to create your question to see if I can get an answer based in physical reality.
 
T

teneo

Always looking for details I may have missed.
I'll take a shot at it: two negatives make a positive from elementary logic. If I say I am not not going to the store that means I *am* going to the store. Applying that to math, negative 3 x negative 4 equals positive 12. At least that's how I learned it after first just memorizing the rule. Good question!
 
mzkitty

mzkitty

I give up.
FaithfulSkeptic said:
Here's another for you folks.

Lets say: b = a
multiply both by a, and you get: ba = a^2
subtract b^2: ba - b^2 = a^2 - b^2
factor: b(a-b) = (a+b)(a-b)
divide both sides by (a-b): b = (a+b)
since a = b (first statement): b = b+b
or
1 = 2
Click to expand...

That is true.
 
jward

jward

passin' thru
Dennis Olson said:
I’m kinda bored, and a random thought popped into my head, and I need someone to explain it.

a positive number times a positive number = a positive number

a positive times a negative = a negative

a negative times a negative = a positive.


WHY IS THAT TRUE?
Click to expand...

Because you implied it is by posing the question. You are our fearless leader. Ergo what you say is true.
...do I win prizes for that?
 
WFK

WFK

Senior Something
FaithfulSkeptic said:
Here's another for you folks.

Lets say: b = a
multiply both by a, and you get: ba = a^2
subtract b^2: ba - b^2 = a^2 - b^2
factor: b(a-b) = (a+b)(a-b)
divide both sides by (a-b): b = (a+b)
since a = b (first statement): b = b+b
or
1 = 2
Click to expand...

Operation not permitted = division by zero.
If a=b then (a-b) equals zero.
 
jward

jward

passin' thru
FaithfulSkeptic said:
Here's another for you folks.

Lets say: b = a
multiply both by a, and you get: ba = a^2
subtract b^2: ba - b^2 = a^2 - b^2
factor: b(a-b) = (a+b)(a-b)
divide both sides by (a-b): b = (a+b)
since a = b (first statement): b = b+b
or
1 = 2
Click to expand...
please check your work. I'm pretty sure that is how ABBA was formed :mus:
 
mole

mole

Doomer Granny
It has to do with the operation of additive inverses.

Start with a positive 3.

Take the opposite of 3, the result is -3 (or the inverse of 3).

Now, take the opposite (inverse) of -3...written as -(-3)

...and voila,the result is a positive 3...right back where we started. :D
 
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