# Solving for a variable

• Sep 2nd 2012, 11:28 AM
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)
• Sep 2nd 2012, 12:26 PM
skeeter
Re: Solving for a variable
Quote:

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 ...

...
• Sep 2nd 2012, 12:40 PM
Re: Solving for a variable
Ooooh, factoring out the L, thank you!

L = 4NV/(V-9)

It was correct :)
• Sep 3rd 2012, 04:27 PM
Wilmer
Re: Solving for a variable
Quote:

Originally Posted by RalphNader
VL-9L=4NV

L-9L=4NV/V

Can you see what you did wrong in that step?