We assume your bet is fair, and we denote $A$ as the event of team One winning, $B$ as the event of team two winning. The Fair Bet Odds Rule says:
In a fair bet, the payoff odds equal the chance odds.
If $A$ happens your profit is $1.7-1=0.7$, if not your profit is $-1$. Assuming a fair bet we get:
$$0.7P(A)-(1-P(A))=0$$ and we get $1.7P(A)=1$ and $P(A)=\frac{10}{17}$. Similarly if $B$ happens you win $0.5$ and lose $1$ if it doesn't. The equation is thus
$$0.5P(B)-(1-P(B))=0$$ and we get $1.5P(B)=1$ and $P(B)=\frac{2}{3}$. We note that probabilities add up to more than 1 in this case since the bookmaker has to take its share.
In some settings you deal with payoff odds. "1.7 to 1" in this case is equivalent to decimal odd of $2.7$. In this scenario:
If $A$ happens you win $1.7$ if it does not happen you lose $1$. The equation is thus:
$$1.7P(A)-1(1-P(A))=0 $$ and $P(A)=\frac{10}{27}$, Similarly if $B$ happens you win 1.5 and lose 1 if it does not. The equation is thus $$1.5P(B)-1(1-P(B))=0$$ and $P(B)=\frac{2}{5}$. In this scenario your probabilities add up to less than one and the $difference\times stake$ is "the house percentage".
Special thanks to @Rodrigo de Azevedo for clarifying the difference between decimal and payoff odds.