Rearranging to solve an equation (quick question)

  • Thread starter Yaaaldi
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In summary, when rearranging for y in the equation x = (y - 2)/(y + 3), you can start by multiplying all terms by y to get rid of the denominator. This will leave you with a second degree polynomial in y, which can be solved in the usual manner. Another important tip is to use parentheses when writing equations to avoid confusion.
  • #1
Yaaaldi
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Homework Statement



Say I had x = y-2 / y + 3

How would I go about rearranging for y= ?

I can't think how to simplify it down to a single y term.
 
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  • #2
If you don't know how to start, just trying playing around with it. My first step would be to get rid of the y+3 in the denominator.
 
  • #3
Multiply all terms by y.
You then have a second degree polynomial in y, which can be solved in the usual manner (assuming y does not depend on x).
 
  • #4
bigfooted said:
Multiply all terms by y.
You then have a second degree polynomial in y, which can be solved in the usual manner (assuming y does not depend on x).

This seems unnecessary to me. One can solve this simply by multiplying and factoring.
 
  • #5
Yaaaldi said:

Homework Statement



Say I had x = y-2 / y + 3
I'm assuming you mean x = (y - 2)/(y + 3). What you wrote is actually x = y - (2/y) + 3.

The lesson is: USE PARENTHESES!
 
  • #6
Mark44 said:
I'm assuming you mean x = (y - 2)/(y + 3). What you wrote is actually x = y - (2/y) + 3.

The lesson is: USE PARENTHESES!

Or use LATEX.
 
  • #7
bigfooted said:
Multiply all terms by y.
You then have a second degree polynomial in y, which can be solved in the usual manner (assuming y does not depend on x).
spamiam said:
This seems unnecessary to me. One can solve this simply by multiplying and factoring.
I'm assuming that bigfooted read the problem as x = y - (2/y) + 3. If it is supposed to be x = (y - 2)/(y + 3) then of course multiplying and factoring would be the way to go.
 

FAQ: Rearranging to solve an equation (quick question)

What is the purpose of rearranging to solve an equation?

Rearranging to solve an equation is a technique used to isolate the variable being solved for and find its value. This allows us to solve for unknown quantities and find the solution to the equation.

How do I know when to rearrange an equation?

You should rearrange an equation when the variable you are solving for is not isolated on one side of the equation. This is often indicated by the presence of other terms or operations on the same side of the equation as the variable.

What are the steps for rearranging to solve an equation?

The steps for rearranging to solve an equation are: 1) Identify the variable being solved for, 2) Move all other terms and operations to the opposite side of the equation, 3) Simplify both sides of the equation, 4) Divide both sides by the coefficient of the variable, and 5) Check your answer by plugging it back into the original equation.

Can I rearrange an equation in any order?

No, you must follow the correct order of operations when rearranging an equation. This means that you should first simplify any parentheses or brackets, then simplify any exponents, and finally perform addition and subtraction from left to right, followed by multiplication and division from left to right.

What are some common mistakes to avoid when rearranging to solve an equation?

Some common mistakes to avoid when rearranging to solve an equation include: 1) Forgetting to perform the same operation to both sides of the equation, 2) Combining like terms incorrectly, 3) Forgetting to distribute a negative sign, and 4) Making a mistake when solving for the variable. It is important to double check your work and make sure all steps are performed accurately.

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