Fiona's steps can be compared to the solution shown below:
Multiplying the binomial and trinomial,
(2X-3)(5X²-2X+7)
Perform multiplication of binomial to trinomial,
=10X³-4X²+14X-15X²+6X-21
Combine same terms and arrange the terms in descending order,
=10X³-19X²+20X-21
Fiona's solution should in the same step shown above.