# Help Solving

• Sep 20th 2010, 03:16 PM
BIOS
Help Solving
Started studying Algebra recently and need help in solving the following:

Make c the subject of the equation:

$ab - ac = bc$

So far i've got:

$ac + bc = ab$

Then i try isolate c on the left:

$\frac {a+b}{c} = ?$

Is that in the right direction? Any tips would be greatly appreciated!
• Sep 20th 2010, 03:21 PM
mr fantastic
Quote:

Originally Posted by BIOS
Started studying Algebra recently and need help in solving the following:

Make c the subject of the equation:

$ab - ac = bc$

So far i've got:

$ac + bc = ab$

[snip]

=> c(a + b) = ab

=> c = ....
• Sep 20th 2010, 03:25 PM
BIOS
$c = \frac {ab}{a+b}$

I don't know how i missed that! Argh. Thanks so much for the reply. Exactly the same type of equation i had problems with yesterday. Extracting the subject when it was multiplied by another variable. Thanks again!