How to prove that x=2\boxed{x = 2} is the same as 2=x\boxed{2 = x}

x=2x2=22x2=0xx2=x2=x2×1=x×12=x\large\begin{aligned} x &= 2 \\ x - 2 &= 2 - 2 \\ x - 2 &= 0 \\ x - x - 2 &= - x \\ - 2 &= - x \\ -2 × -1 &= -x × -1 \\ 2 &= x \end{aligned}

Therefore, x=2 is the same as 2=x\text{Therefore, \boxed{x = 2} is the same as \boxed{2 = x}}

Just for clarification, this is meant to be a joke note, made due to a dare some friend of mine gave :)

Note by Frisk Dreemurr
3 weeks, 2 days ago

No vote yet
1 vote

  Easy Math Editor

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

When posting on Brilliant:

  • Use the emojis to react to an explanation, whether you're congratulating a job well done , or just really confused .
  • Ask specific questions about the challenge or the steps in somebody's explanation. Well-posed questions can add a lot to the discussion, but posting "I don't understand!" doesn't help anyone.
  • Try to contribute something new to the discussion, whether it is an extension, generalization or other idea related to the challenge.
  • Stay on topic — we're all here to learn more about math and science, not to hear about your favorite get-rich-quick scheme or current world events.

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold

- bulleted
- list

  • bulleted
  • list

1. numbered
2. list

  1. numbered
  2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1

paragraph 2

paragraph 1

paragraph 2

[example link]( link
> This is a quote
This is a quote
    # I indented these lines
    # 4 spaces, and now they show
    # up as a code block.

    print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in \( ... \) or \[ ... \] to ensure proper formatting.
2 \times 3 2×3 2 \times 3
2^{34} 234 2^{34}
a_{i-1} ai1 a_{i-1}
\frac{2}{3} 23 \frac{2}{3}
\sqrt{2} 2 \sqrt{2}
\sum_{i=1}^3 i=13 \sum_{i=1}^3
\sin \theta sinθ \sin \theta
\boxed{123} 123 \boxed{123}


Sort by:

Top Newest

@Frisk Dreemurr Your proof is just cancelling out or rearranging, throughout the whole proof, in a mathematical perspective, you have not changed the equation!

Shevy Doc - 3 weeks, 1 day ago

Log in to reply

Yes, that is why I thought to post it. It looks interesting, and not all know/tried to prove that 2=x2 = x is the same as x=2x = 2 before, they just take that fact for granted :)

And yes, mathematically, they are the same equation

Frisk Dreemurr - 3 weeks ago

Log in to reply

Its still useless. x = 2 says that their values are equal, so 2 = x doesn't convey more info and is useless. Also, there's an easier way to do what you did -

x = 2

-x = -2 (multiply by -1 on both sides)

2 = x (transposition, so -x becomes x on RHS and -2 becomes 2 on LHS)

This note isn't actually very interesting or effective. in all honesty. No offense @Frisk Dreemurr.

PS - Just finished the Atlantis Complex (7th book) and I'm dying, its awesome! BTW, today is Artemis Fowl's birthday, Sep 1st :)

Percy Jackson - 2 weeks, 4 days ago

Log in to reply

@Percy Jackson LOL, the challenge was to only use core traditional methods, so no transposition as well

Plus, I didn't mean this note to be much useful/interesting, as I made it for a joke :)

Frisk Dreemurr - 2 weeks, 4 days ago

Log in to reply

dont most of us know this it is simple algebra and most people cover this as a basic fundamental when they learn it in school its basically the same as learning operations in primary school and fractions and stuff its just that you add letters and mumbo jumbo language intoit to make a mixture of math that is good and useful if done right but sticky and messy if done wrong

Nathan Soliman - 4 days, 14 hours ago

Log in to reply

Exactly @Nathan Soliman, see @Frisk Dreemurr, even the 13 year old preschooler gets it, no offense 'Ethan' :)

Percy Jackson - 4 days, 11 hours ago

Log in to reply

none taken son

Nathan Soliman - 3 days, 15 hours ago

Log in to reply

@Nathan Soliman haha very funny, I doubled over............................................................................................(note the sarcasm)

Percy Jackson - 2 days, 22 hours ago

Log in to reply

@Percy Jackson ok percy percy jackson jackson (implying the double)

Nathan Soliman - 2 days, 18 hours ago

Log in to reply

@Nathan Soliman .......................that isn't even worth replying to.

Percy Jackson - 2 days, 17 hours ago

Log in to reply

@Percy Jackson .......................that isn't even worth replying to.

Nathan Soliman - 1 day, 16 hours ago

Log in to reply


Problem Loading...

Note Loading...

Set Loading...