Answer: -72a^3 +108a^2
Collect like terms
(2a)(6a)(2a-8a+9)= (2a)(6a)(-6a+9)=12a^2(-6a+9)
= -72a^3 +108a^2
First you need to give both fractions a common denominator lets say 40. So N would be 8/40 and Z would be 35/40, so Z collected more than N. All together they collected 43/40 which simplifies to be 1 and 2/40 which would again simplify to 1 and 1/20.
I-1 is the polynomials because I is the linear term and 1 is the constant