What is the asymptotic distribution for the turning point of the wage equation as a function of education?

Thanks for your help, please provide step by step solution, then I can get a comprehensive understand, thanks in advance

wagesi = educi + deducif + 1339 + um = 1, . . . , n, where \"(E denotes the wage of the i-th individual, educi their level of educational attainment, and is a vector of observations on all the other expanators in the equation (including the intercept). Note that we have said nothing about how any of these variables are measured. In any event, the postulated model allows for a quadratic relationshp between wages and education and an obvious question to ask is where is the turning point in the relationship between wages and education given the X's. Elementary mathematics tells us that this occurs where educz- = [[ 25 2. Suppose that the joint asymptotic distribution of \"3131651" is of the form A (E r: N 5 7 7771 0,65 0'3 (59 9 9 E 266 39 5 5 0% \"as :59