Question 757355
When solving proportions the first step is usually to cross multiply.

{{{(b-3)/5 = 2/b}}}

{{{b(b-3) = 2(5)}}}

{{{b^2-3b = 10}}}

{{{b^2-3b-10=0}}} Now we have a quadratic equation which we can factor

{{{(b-5)(b+2)=0}}}

Setting both binomials equal to zero we get that b = 5 or -2.