What's negative 3 multiplied by negative 3?

# Challenge Math and Brain Teaser Problems!

**Stradyvarious**#124

You didn't say negative 3 was the square root of 9.

And now your saying negative 3 is!

**Stradyvarious**#126

9 is the result of negative 3 multiplied by negative 3.

So the square root of 9 is negative 3.

**Dolphin_coders**#127

Oh ok, but both negative and positive 3 times by it self equals 9

Where'd you get that from? (As in the Q)

**t1_hopscotch**#128

Now that you mention, I looked back through that Murderous Maths book, (I admit I really like it and don't know how much is fair use in relations to showing contents of the book, but I suppose it would be the same if anyone looked at a sample of it...I should be more careful, but I will show this, I just like these hehe)

I have not looked at this for a long time so I do not know the answer! (They are in the book though)

**MR.GAM3R**#129

That is interesting (I have probably said this recently about math stuff tons of times xD). This works for all other square roots, too.

**MR.GAM3R**#130

This is pretty obvious, and probably doesn't count as an answer, but what about 10/30? Cross out the 0's and get 1/3

**t1_hopscotch**#131

Ooh wow I would not have thought about that!! They had another answer but I don't think they had thought about the ones with 0s

**JonnyGamer**#132

He he, very funny

Yeah, I did a lot of work on this too (3 pages of work actually). My friend tried to solve it as well and we both got negative areas (-70 and -83). I'm going to read through your work and also try and solve it again, but it a more organized fashion.

Also, I edited it in later, the side length of the pentagon is 1 (to make it easier checking your work)

Did you solve the area of the green area? (Sorry, I was trying to look around. What did you happen to get?)

**ColorlessCanvas**#133

but you never mentioned the answers for both questions corresponded.

You can have -3^2 or 3^2 equal the answer of 9. The square root should be plus or minus 3.

**t1_hopscotch**#134

Ooh hmm I didn't want to go too far so I had only the lengths that I had put (haha yep I just set the side lengths to x, I guess I'm just used to trying to generalise so it could be used for a pentagon with any side length)

I am suspecting that there are gaps in the circle where the star does not cover it but am not sure if there are:

**JonnyGamer**#135

The pentagon is inscribed inside the circle (so all five points of the pentagon are on the circle as well)

**MR.GAM3R**#137

@Stradyvarious the largest number you can enter in my program is about 3 quintillion, or exactly 3,074,457,345,618,258,602. (Which still follows the rule!)

EDIT: I have changed my program to work with massive numbers. It works with 1000! (1000 factorial) but it takes forever

**t1_hopscotch**#138

Woah that is awesome!!

And ooh I thought about this more too, and I see now that because the vertices of the pentagon are on the circle, if you extend lines from them beyond the circle, i think it won't have the gaps inside the circle that I was talking about before.

So from that, i can work out the shaded area from my diagram = `five orange triangles + area of middle circle - (area of the five unshaded segments in the middle circle)`

**JonnyGamer**#139

I took this problem form my math blog I just created!

Question 1: Difficulty 10

Find the smallest nonzero solution

(x^2) - 313(y^2) = 1

Who can solve it??

@t1_hopscotch

**t1_hopscotch**#140

Ooh I will take a look at your new problem too @JonnyGamer

I have no idea about the correctness of this `¯\_(ツ)_/¯`