Step-by-step explanation:
we multiply both sides by the denominator on the right to eliminate fraction, so we have..
p*(n+a)= (n²+a/n+a)*n+a
so we have
p(n+a)= n²+a
so opening the bracket on the left hand side we have,
p*n+p*a
pn+pa
so,
pn+pa= n²+a
so collecting like terms we have,
pn-n²= a-pa
so removing a from the equation on the right hand side we have,
pn-n²=a(1-p)
dividing both sides by the equation in the bracket on the right hand side, we have..
pn-n²/(1-p)= a
a = pn-n²/1-p
or
a = n(p-n)/1-p
