Subject of formula

Question

Hey guys, 

 

I am confused with this question, I need help.

 

Make (a) the subject of the formula

 

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

 

 

Is the answer: A=-pb-pb/p-q

Answer 1

I assume that you mean:  solve the equation for a.  

 

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

 

pa + pb = qa - qb

 

pa-qa = -pb-qb

 

a(p-q) = -pb-qb

 

a = (-pb-qb)/(p-q) = -b(p+q)/(p-q)