Find the maximum profit and the number of units that must be produced and sold in order to yield the maximum profit. Assume that revenue, Upper R left parenthesis x right parenthesis

R(x), and cost, Upper C left parenthesis x right parenthesis

C(x), are in thousands of dollars, and x is in thousands of units.

R(x)=7x-2(x)^2

C(x)=x^3-4(x)^2+2x+1