The average annual income, I, in dollars, of a lawyer with an age of x years is modeled with the following function:

I=-425x²+45,500x-650,000


According to this model, at what average age do lawyers earn their maximum average annual income?

Round to the nearest year.
The average annual income, I, in dollars, of a lawyer with an age of x years is modeled with the following function:

I=-425x²+45,500x-650,000


According to this model, at what average age do lawyers earn their maximum average annual income?

Round to the nearest year.