Government economists in a certain country have determined that the demand equation for soybeans is given by
p = f(x) = 57/(2x2 + 1)
where the unit price p is expressed in dollars per bushel and x, the quantity demanded per year, is measured in billions of bushels. The economists are forecasting a harvest of 2.2 billion bushels for the year, with a possible error of 10% in their forecast. Determine the corresponding error in the predicted price per bushel of soybeans. (Round your answer to one decimal place.)