Rearranging Formulas for a and b: Common Mistakes and Correct Answers

  • Thread starter thomas49th
  • Start date
In summary, the conversation is about rearranging a formula to get variables a and b on their own. The speaker presents their own answers for both variables and notes that they are different from the "real answer". They ask for help in finding where they went wrong. The other speaker suggests that the answers are correct but just written differently. They also suggest a possible error in the second equation.
  • #1
thomas49th
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Hi, I have to rearrange the formula to get a and b on their own. The real answers are different to mine:

p(a + b) = q (a-b) [a]

pa + pb = qa - qb

pa-qa = -qb - pb

a (p-q) = -qb - pb

a = (-qb - pb)/(p-q)

and the real answer is:

(qb + pb)/(q -p)

it's differnet to mine!

And finding rearranging to get b is

p(a + b) = q (a-b) [a]

pa + pb = qa - qb

pa-qa = -qb - pb

pb + qb = qa - pa

b(p + q) = qa - pa

b = (qa - pa)/(p + q)

and the real answer is

(pa + pa)/(q + p)

Errrrrr!

Can someone so me where i went wrong

Thanks
 
Last edited:
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  • #2
It's not that your answers are wrong, I think they are done properly. They just don't look exactly the same. For "a", I think that perhaps if you multiplied through by -1 after a(p-q)=-qb-pb, and arranged it based on that, your answer would turn out looking the same as the "real answer". To check, you can plug numbers into the equations and see if they turn out the same.
For "b", just change the order of p and q, it's addition anyway so it won't change anything.
 
  • #3
(-qb - pb)/(p-q) is equivalent to (qb + pb)/(q -p) just multiply top and bottom by -1.

for the second one you have may a misprint... check what you have typed
 

What could be the reason for my answers being wrong?

There could be several reasons for your answers being wrong. It could be due to a lack of understanding of the topic, errors in calculations, or misinterpreting the question. It is important to carefully review and double-check your work to identify the reason for the wrong answers.

How can I improve my accuracy and reduce wrong answers?

To improve your accuracy and reduce wrong answers, it is important to practice regularly and develop a strong understanding of the subject. Additionally, pay attention to details, use reliable sources, and seek help from teachers or peers if needed. It is also helpful to take breaks while studying to avoid mental fatigue.

What should I do if I consistently get wrong answers?

If you consistently get wrong answers, it is important to identify the root cause of the issue. It could be a lack of understanding, poor study habits, or test anxiety. Seek help from teachers or tutors, practice regularly, and try different study techniques until you improve your accuracy.

Are there any common mistakes that lead to wrong answers?

Yes, there are some common mistakes that can lead to wrong answers. These include misreading the question, incorrect use of formulas or equations, calculation errors, and copying incorrect information. It is important to be mindful of these common mistakes and take steps to avoid them.

Should I worry if my answers are wrong?

No, you should not worry if your answers are wrong. Making mistakes is a part of the learning process. Instead of getting discouraged, use your mistakes as an opportunity to learn and improve. Seek help if needed and keep practicing to get better at the subject.

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