Samantha puts an initial $500 into a savings account. The account has a 4% annual compound interest rate. What is the equation that best represents Samantha's account?

Hint: Use the formula y = P(1 + r)x.

y = 500(1.4)x
y = 500(0.04)x
y = 500(1.04)x
y = 500(0.4)x