4) Jill sells dolls at a local farmers market. As Jill produces a greater number of dolls, she can
lower the price per unit. The function v(x)=49-2x relates the price v to the number
produced x. The cost c of making x dolls can be represented with the function c(x)=12x+64.
How many dolls should Jill sell each week to maximize her profit P?