man im taking college alegebra next year in grade 11

Is that even allowed?

 

Who knows...he was a weirdo. :lol:

okay, this might sound silly, but has anyone ever understand why when you multiply a negative number with another negative, you get a positive number?

 

I just try to get an example or imagine something that would prove me that, but I can't get it..... it's like fine, I follow the rule but I can't understand why it does that!

 

The other one is for example -7--7 ends up being zero, but that one I get it by, I suppose, thinking it is the say as "no, he's not not here" (or something like that, that means yes)

 

For the subraction, imagine it on a number line. You're at -7, and you want to subtract another -7. If you were just subtracting 7, you'd move "left" on the number line to -14, but since you're subtracting a negative number, you move the opposite direction, back to 0. The same principle applies to the multiplication. I may sound like I'm talking to a baby, but I actually had to explain this to another college-age person a few weeks ago. :stunned: Also, the double-negative thing works too. :P

 

I get the first one, the addind thing, but the multiplying no....... the thing is, I can't find the logic on the rule!

 

i.e : -2 x -5 = 10

 

The multiplication is suppose to be a fast way of adding, so it would be either -2+-2+-2+-2+-2 or -5+-5. Non of those cases gives you 10, hence I don't see the logic in it!!

Is that even allowed?

 

Who knows...he was a weirdo. :lol:

 

:lol: Are math teachers always weird? Mine always wore hooded sweaters with nothing under them and he would wear it unzipped a little bit so his tufts of gray chest hair would stick out the top. :confused:

man im taking college alegebra next year in grade 11

cool eric

Fuck Math.

:cool:

That's right.

I once had a weirdo geometry teacher. When he got pissed he would throw markers out the window.

Are math teachers always weird? Mine always wore hooded sweaters with nothing under them and he would wear it unzipped a little bit so his tufts of gray chest hair would stick out the top.

:lol: yikes... :stunned:

I once had a weirdo geometry teacher. When he got pissed he would throw markers out the window.

 

:/ He must have had to spend a few bucks on markers throughout the year.

I get the first one, the addind thing, but the multiplying no....... the thing is, I can't find the logic on the rule!

 

i.e : -2 x -5 = 10

 

The multiplication is suppose to be a fast way of adding, so it would be either -2+-2+-2+-2+-2 or -5+-5. Non of those cases gives you 10, hence I don't see the logic in it!!

 

If you're doing -5+-5 that would be like multiplying by 2, not -2. If multiplication is a fast way of adding, then look at multiplying by a negative as a fast way of subtracting. So -5x-2 is like -5--5. Get it? :)

I get the first one, the addind thing, but the multiplying no....... the thing is, I can't find the logic on the rule!

 

i.e : -2 x -5 = 10

 

The multiplication is suppose to be a fast way of adding, so it would be either -2+-2+-2+-2+-2 or -5+-5. Non of those cases gives you 10, hence I don't see the logic in it!!

 

If you're doing -5+-5 that would be like multiplying by 2, not -2. If multiplication is a fast way of adding, then look at multiplying by a negative as a fast way of subtracting. So -5 x-2 is like -5--5. Get it? :)

 

yes! and -5--5 it's 0!!! not +10

oh yeah. I probably should have thought that one out a little more. :lol:

 

uh... well in that case, I don't know why, it just is. :P

:lol: I just got to the same conclusion! But then something maked sense, thought I can remember now how it was, but I've got the impression or the "vague idea" that it did!

ahh integers!

we're learning them right now, but we just started so we're on adding.

i'll probably check this thread when i'm on to multiplication for integers.

:lol: I learned like a week ago what integres were.......... are really........ we just called them whole numbers!

I remember now Mr. Peed! -5 x -2 means according to you -5 - -5, but I thought that it makes much more sense that: it's the same -5 x -5 but you put a - sign next to both = --5 x --5, which gives + 10 .... at least that maked sense to me, and looked rational! :D