Is this correct?

This expression uses all three variables: a, b, and c.
2b – a It is a rational expression with a divisor of 2b – a.
The integers have been plugged in for the variables.

Both numerator and denominator have been evaluated.
Both are negative which means the answer will be positive.
This is our answer in lowest terms, and I will leave the
answer as an improper fraction.

I have use my birthday she wanted B to be a
negative number... a=4, b= -30, c=85

−30−85/
(2)(−30)−4
=
−115/
(2)(−30)−4
=
−115/
−60−4
=
−115/−64
=
115/64

Question

Is this correct?

This expression uses all three variables: a, b, and c.
 2b – a It is a rational expression with a divisor of 2b – a.
  The integers have been plugged in for the variables.
 
 Both numerator and denominator have been evaluated.
  Both are negative which means the answer will be positive.
 This is our answer in lowest terms, and I will leave the
  answer as an improper fraction.

I have use my birthday she wanted B to be a 
negative  number... a=4, b= -30, c=85






−30−85/
(2)(−30)−4
=
−115/
(2)(−30)−4
=
−115/
−60−4
=
−115/−64
=
115/64