# Math Help - Solving for a variable

1. ## Solving for a variable

This is the problem that I cannot figure out, I am awful at solving for variables. If someone could please explain this to me it would be much appreciated!

Solve for L:

V=9L/(L-4N)

This is what I did, which was incorrect:

V(L-4N)=9L

VL-4NV=9L

VL=9L+4NV

VL-9L=4NV

L-9L=4NV/V

-8L=4NV/V

L=4NV/(-8V)

L=NV/(-2V)

2. ## Re: Solving for a variable

Originally Posted by RalphNader
This is the problem that I cannot figure out, I am awful at solving for variables. If someone could please explain this to me it would be much appreciated!

Solve for L:

V=9L/(L-4N)

This is what I did, which was incorrect:

V(L-4N)=9L

VL-4NV=9L

VL=9L+4NV

VL-9L=4NV

L(V-9) = 4NV

now finish it ...
...

3. ## Re: Solving for a variable

Ooooh, factoring out the L, thank you!

L = 4NV/(V-9)

It was correct

4. ## Re: Solving for a variable

Originally Posted by RalphNader
VL-9L=4NV

L-9L=4NV/V
Can you see what you did wrong in that step?