You can put this solution on YOUR website! When you are asked to 'solve for' a specific varialbe, you are being asked to setup an equation that relates that one varialbe to all the others. Basically you are being asked to 'get k by itself on one side, and everything else on the other'.
Given Solve for k
You can put this solution on YOUR website! There are 2 main things to know
1) You have to get all by itself on one side of the equation
2) Anything you do to one side, you MUST do to the other side
So, first
Subtract from both sides
This is the same thing as adding these 2 equations together
Notice that the and the on the right side cancel
So, now you have
Now divide both sides by
On the right side, the in the denominator cancels the
in the numerator
Now you have
Now just rewrite the equation in the opposite direction
And that's the answer