Rearranging the subject of an equation help please

  • MHB
  • Thread starter sarannie
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In summary, to rearrange the formula to make b the subject, you would start by expanding the brackets and collecting terms with b on one side. Then, you can clear the fraction by multiplying both sides by 3. This will result in the formula: b = \frac{3c^2+6a-abc}{a}.
  • #1
sarannie
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Please please can you help me understand how to rearrange this formula to make b the subject:
abc/3=c^2+a(b+2)
 
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  • #2
Start by expanding the brackets, moving every term that has a "b" to one side, and taking b out as a factor.
 
  • #3
Prove It said:
Start by expanding the brackets, moving every term that has a "b" to one side, and taking b out as a factor.

Thank you, I have an absolute mental block with algebra.
So do I do a x b a x 2 next?
 
  • #4
sarannie said:
Thank you, I have an absolute mental block with algebra.
So do I do a x b a x 2 next?

Hi there,

Yep, I think I know what you mean and if so that's the right idea. After expanding you'll get this:

\(\displaystyle \frac{abc}{3}=c^2+ab+2a\)

Now what you should do is collect the terms with a "$b$" in them on one side and terms without on the other. If you do that you'll get this:

\(\displaystyle \frac{abc}{3}-ab=c^2+2a\)

With me so far? Any idea what to do next?
 
  • #5
You are very good to help me, thank you.
I'm wondering about clearing that fraction by multiplying by 3?
 

FAQ: Rearranging the subject of an equation help please

How do I rearrange the subject of an equation?

Rearranging the subject of an equation involves isolating the variable you want to solve for on one side of the equation. This can be done by using inverse operations, such as addition, subtraction, multiplication, and division, to move all other terms to the other side of the equation.

Why is it important to know how to rearrange the subject of an equation?

Rearranging the subject of an equation allows us to solve for a specific variable, which is often necessary in solving real-world problems. It also helps us better understand the relationship between different variables in an equation.

What are some common mistakes when rearranging the subject of an equation?

Some common mistakes include forgetting to perform the same operation on both sides of the equation, incorrectly distributing a negative sign, and forgetting to change the sign of a term when moving it across the equal sign.

Are there any shortcuts for rearranging the subject of an equation?

There are no shortcuts for rearranging the subject of an equation, but there are some tips that can make the process easier. These include keeping track of the operations performed on each side of the equation and checking your work by plugging the solution back into the original equation.

Can I rearrange the subject of any equation?

In most cases, yes, you can rearrange the subject of an equation. However, there are some equations, such as those involving radicals or logarithms, where rearranging the subject may not be possible. It is important to understand the restrictions of the equations and use appropriate methods to solve them.

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