Alright, let's factor this to get the answer.
3k^2-10k+7
To find the factors, we want to think "What will add up to -10, and multiply to (+)7?"
Because the leading coefficient is 3, we know that we can take one factor of 7 and multiply it by 3.
Thus, this factors to
(3k-7)(k-1)
(if you FOIL it it should come out to be the original equation)
From this, set both of those [(3k-7) and (k-1)] equal to zero and solve
3k-7=0
3k=7
/3
k=7/3
or
k=1