Calculating 3a-7b: Solving the Expression (2a-b-3)^2 + (3a+b-7)^2 = 0

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Discussion Overview

The discussion revolves around solving the expression (2a-b-3)² + (3a+b-7)² = 0 to determine the value of 3a-7b, focusing on the implications of the equation and potential methods for finding a and b.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant suggests that the solution could involve finding a and b separately or directly calculating 3a-7b from the given equation.
  • Another participant notes that with one equation and two unknowns, there could be many solutions depending on what cancels out, recommending multiplication of terms to explore possibilities.
  • A participant expresses difficulty in manipulating the equation to isolate 3a-7b, indicating that multiplication alone does not clarify the situation.
  • Another participant introduces a reformulation of the equation as c² + d² = 0, questioning the conditions under which this holds true for real numbers.
  • It is proposed that c and d must both equal zero for the equation to hold, leading to a system of two equations with two unknowns.
  • Participants acknowledge the realization of the underlying conditions of the equation, with one expressing gratitude for the insight shared by another participant.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method to solve for 3a-7b, with multiple approaches and interpretations of the equation being discussed. The discussion remains unresolved regarding the specific steps to take next.

Contextual Notes

Participants highlight the challenge of working with one equation and two unknowns, indicating potential limitations in deriving a unique solution for 3a-7b without additional information.

Chuckster
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If [tex]a[/tex] and [tex]b[/tex] are real numbers, and we know that [tex](2a-b-3)^{2} + (3a+b-7)^{2}=0[/tex], how much is [tex]3a-7b[/tex]

Any ideas on this? I'm guessing the solution can go two ways: either i find a and b separately, or i calculate the expression above somehow and i'll be left with 3a-7b
 
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Chuckster said:
If [tex]a[/tex] and [tex]b[/tex] are real numbers, and we know that [tex](2a-b-3)^{2} + (3a+b-7)^{2}=0[/tex], how much is [tex]3a-7b[/tex]

Any ideas on this? I'm guessing the solution can go two ways: either i find a and b separately, or i calculate the expression above somehow and i'll be left with 3a-7b

You're answering your own question. :smile:

Since you would have 1 equation and 2 unknowns, there can be many solutions depending on what cancels out. Your best bet is to multiply stuff out and see what happens.
 
gb7nash said:
You're answering your own question. :smile:

Since you would have 1 equation and 2 unknowns, there can be many solutions depending on what cancels out. Your best bet is to multiply stuff out and see what happens.

The key word would be somehow. If multiplication worked, i wouldn't be asking how :).

Anyway, i get a bunch of junk, and i can't seem to figure out what to do with it. How to create or find 3a-7b, that is...
 
Ahh, I see what's going on.

At first glance, I would go with multiplication. However, there's something special about this equation. I'll replace it with this equation:

c2 + d2 = 0, where c and d are real numbers.

What's the only way this could happen? What must c and d be equal to?
 
gb7nash said:
Ahh, I see what's going on.

At first glance, I would go with multiplication. However, there's something special about this equation. I'll replace it with this equation:

c2 + d2 = 0, where c and d are real numbers.

What's the only way this could happen? What must c and d be equal to?

It's possible if c and d are both equal zero!
Then i just solve the system of 2 equations with 2 unknowns.

THANKS gb7nash!

(hate it when i miss obvious catches)...
 
You got it. :smile:

It's ok, I missed it too.
 

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