what is sin^2 a-36 over sin^2 a +12 sin a +36 simplify with steps

Question

thank you 

Answer 1

The numerator factors as (sin(a) +6) (sin(a) -6)

The denominator factors as (sin(a) + 6 ) (sin(a) +6)

 

On dividing, there is a cancellation of a factor of (sin(a) +6)  with the resuilt

 

(sin(a) -6) / (sin(a) +6)