Can someone help me with the steps to solve this problem?

Darius bought a flat-screen TV for $2200. The value decreases by about 18% each year. How long will it take for the value to be reduced to $500.

My Algebra 2 teacher taught us the formula y = abx where x is an exponent, so I already set up the equation.

500 = 2200(.18) power of x

i got .863 as x but I don't know how long that is in time or if I even did it right.