Quick question: x^2-y^2=16 (find x)

[sobergeek23]

Very much so: there even are sanctions. For good reasons. We would get into trouble with teachers no end, for example.

From Info | terms and rules :

• Giving Full Answers:
  On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Complete solutions can be provided to a questioner after the questioner has arrived at a correct solution. If the questioner has not produced a correct solution, complete solutions are not permitted, whether or not an attempt has been made.

thats stupid because I am my post under my attempt i obviously did try..i only asked for an answer when you made your response complicated..anyway in your last post you said "no because it isn't correct" gee thanks for the help...helpful wouldve been if you posted whatever rule made it not correct..

 

[vantroff]

Because how the distributive, associative and commutative properties work. And where they work. (at least that what I think)

(ab)² = a²b²
Why? Because (ab)² means (ab)*(ab)=ab*ab=aa*bb=a²b²
But,

(a+b)² = (a+b)(a+b)=a(a+b)+b(a+b)=a²+ab+ba+b²=a²+2ab+b² ≠ a²+b²

We can think for the thing in the parentheses like x.
x=a+b
So, x^2=x*x=(a+b)(a+b)

I hope I didn't made some mistake...

 

[BvU]

thats stupid because I am my post under my attempt i obviously did try..i only asked for an answer when u made ur response complicated..anyway in ur last post u said "no because it isn't correct" gee thanks for the help...helpful wouldve been if u posted whatever rule made it not correc

I don't mind being shown wrong, but I don't like being called stupid. I did not just say it was incorrect, I even gave you an example where you could see for yourself that $(2+3) * (2+3) \ne 2^2 + 3^2$.

I tried to help you and apparently failed. So I give up and leave it to others -- if any -- to help you with your problems.

 

[berkeman]

Thread closed for Moderation...

 

[berkeman]

is it aginst forum policy to give out answers?

Very much so: there even are sanctions. For good reasons. We would get into trouble with teachers no end, for example.

thats stupid because I am my post under my attempt i obviously did try.

It is definitely our policy here, and is clear in the PF rules (under INFO at the top of the page) that you agreed to when joining here. One of our most important themes here at the PF is to help students learn how to learn. That means that our tutorial help efforts are limited to finding mistakes, asking questions, giving hints, etc. But posting the answer is strictly forbidden here.

You were very close to figuring out the answer on your own with their hints and the mistakes that they found and pointed out. I especially like the post that showed you an example multiplication to try to see where your misunderstanding was.

I don't mind being shown wrong, but I don't like being called stupid

I don't think the OP was calling you stupid, I think she was saying that the PF policy of not giving students answers is stupid. Not the first time a student has posted that...

 

[berkeman]

After a *lot* of cleanup and reminding some posters not to post answers to homework questions at the PF, the thread is re-opened. The OP may have what she needs for her homework, or she may have clarifying questions still.

 

[Kaura]

i couldn't find my other response but is it because the plus sign is there that we can't distribute the squared (x+y)^2 into x^2+y^2?

Suppose we have a square with side length a+b then the area would be (a+b)²
In this high quality graphic suppose that the red part of the side length is a and the blue is b
What would the total area be?