x + 5 quotient
x-4 ) x2 + x -17
x2-4x (subtract)
5x
5x - 20 (subtract)
3 remainder
(x2+x-17)/(x-4)=(x+5)+3/(x-4).
CHECK: (x+5)+3/(x-4)=[(x+5)(x-4)+3]/(x-4)=
(x2+x-20+3)/(x-4)=(x2+x-17)/(x-4)✔️
Synthetic division:
4 | 1 1 -17
1 4 | 20 (add)
1 5 | 3 = x+5 remainder 3