Can anybody solve these two equations with two unknowns for me?

$\displaystyle \frac{a}{a+b}$= $\displaystyle \frac{4}{102}$, and

$\displaystyle \frac{a*b}{(a+b)^2(a+b+1)}$ = 0.0003658

Basically I am doing a Statistics question about beta distribution and this has cropped up during the question, and when i get my answers, i keep gettin 'a' as a negative number (which is not permitted in beta distribution)

Thanks