t5 + t4 + t3 - t2 + t + C
C is an arbitrary constant term.
-t2 is a term with degree of 2, since the exponent of t is 2 and with a coefficient of -1.
The first term has an exponent of 5 since the overall polynomial is of degree 5.
Some key degrees you want to know:
1st degree indicates straight line polynomial.
2nd degree indicates parabolic polynomial.
3rd degree indicates cubic polynomial (looks like an S-shape curve).