Posted by **sophmore** on Wednesday, September 13, 2006 at 6:15pm.

how do you isolate a variable?

my teacher gave us questions and we are suppose to isolate the variable x

PLEASE HELP!

x + 3y = 11

You isolate it by moving everyting to the other side except that variable. Thus

x + 3y = 11 is the same as

x = -3y + 11

If tne x had been multiplied by some number then you would need to divide both sides by that number to get x standing alone on one side.

To expand on what Roger has said, isolating x means to get x on one side and everything else on the other. If we use x + 3y = 11 as an example, x is already on one side. And 11 is ok where it is. But we need to move 3y from the left to the right so we subtract 3y from both sides. (We can get away with changes like this if we do to both sides what we do to one side.)

x + 3y - 3y = 11 - 3y.

The +3y and -3y on the left add to zero and we are left with

x = 11 - 3y

Thnx for pointing that out. I see I said to simply 'move everything to the other side' without giving any rules for doing that. That's a little too informal in hindsight...

- math -
**Alissa**, Monday, February 9, 2009 at 7:06pm
isolating the variable

## Answer this Question

## Related Questions

- math - So how would you isolate the variable of 3z=5? My mom is trying to help ...
- Math - Need help with this problem: Isolate the variable: -4(2x - 7) = -36
- MAth - 4+sqrt(4+x^2)=x, I need to isolate the x variable in the radical ...
- math - how to isolate a variable with a component. 60+80x1 over 2 to the ...
- math - how to isolate a variable with a component. 60+80x1 over 2 to the ...
- Math - Here is the math problem. 150 is 75% of what number? I know the rate is ...
- organic chemistry - urgent, please help me...this is about the separation and ...
- chemistry - Aniline (MW93 g/mol) co-distills with water 98.2 C. The vapor ...
- MATH PLEASE HELP! - HOW DO YOU MAKE -4.2 A ONE, HOW DO YOU ISOLATE IT OR DO ...
- math - find the slope and y-intercept of the graph of the equation. explain each...