1. ## solve for p

a-p = (a+p)/b

the answer is p = [a(b-1)] / (b+1) but I don't know how to get from the beginning to the solution.

2. $a-p = \frac{a+p}{b}$

First remove the fractions:

$b(a-p) = a+p$

Expand:

$ab-bp = a+p$

Move the p to the same side and the other to the other side.

$p + bp = ab - a$

Factorise p and a:

$p(1+b)=a(b-1)$

Divide by (1+b) on both side to have p alone.

$p = \frac{a(b-1)}{1+b}$ or $p = \frac{a(b-1)}{b+1}$

3. Thanks!!

4. You're welcome