[The Swedish krona's currency has gone down by half during a 15-year period. Calculate the yearly procentual decline, if we assume the decline has been the same each year.]

So here is what I have tried;

x^15 = x / 2

2x^15 = x

2 = x / x^15

2 = x^14

2^1/14 = x

x = 1.057

Wrong....

x^15 = 0.5

x = 0.5^1/15

x = 0,9548

Wrong.... but It could be right because x (is almost) = 0,955. Might be that

1-0.955 = 0.045 = 45%.

aha.. that would be that the diffirence, thus the DECLINE would be 45% not the incline. The diffirence might be calculated from the aspects of 100%... someone please correct me on this one