susan bought a 6 month $1,700 certificate of deposit.At the end of six months she received $63 simple interest. what annual rate of interest did the certificate pay?

In a year then it would be 2 times $63

So $1700 times the rate of interest (we will call it X) will equal the interest.
Thus the equation

1700X=(63)(2)
solve for x

X=.074

or 7.4%