solve 1 + 3x = -2x - 9 for x

[Jackson332006]

1 + 3x = -2x - 9

(3x +1)+(-1 + 2x) = (-2x - 9) + (-1 + 2x)

Not sure if this is the proper way to go about finding x. Can anyone help me?

Thanks A lot!!!!

 

[tkhunny]

Re: solve for x

1 + 3x = -2x - 9

Not sure if this is the proper way to go about finding x.

"Proper"? How about a way that works and can be repeated and understood?

1 + 3x = -2x - 9

Goal: Get 'x' alone.
First: Group them together.

Add 2x

1 + 3x + 2x = 2x - 2x - 9

Simplify

1 + 5x = -9

Subtract 1

5x = -10

Divide by 5

x = -2

Check in ORIGINAL expression

1 + 3x = -2x - 9
1 + 3(-2) = -2(-2) - 9 ???
1 - 6 = 4 - 9 ??
-5 = -5 !! Check

Rules to live by:

Rule #1: NEVER combine steps.

Rule #2: Once you are sufficiently familiar with what you are doing, so that you have NO desire to wonder or question, go ahead and combine steps that can be aggregated logically.

Rule #3: If you combine steps, and cannot check your work or remember what you did, please refer to Rule #1.

One step at a time.
Organized.
Follow and understand your own work.
No guessing.

 

[Jackson332006]

Thank you all for your help and Information.