This can be written -16(x²-25x/4-5/8)=-16(x²-25x/4+625/64-625/64-40/64).
This reduces to -16((x-25/8)²-665/64)=-16(x-25/8)²+665/4.
When x=25/8 this expression has a maximum value of 665/4.
There are no constraints on the domain so the domain is (-∞,∞) while the range is (-∞,665/4).