# The total revenue received from the sale of x units of a product is given by $R(x) = 13x^2 + 26x + 15$ Find the marginal revenue when x = 7.

Marginal revenue is the rate of change of total revenue w.r.t the number of units sold.

Marginal revenue (MR)=dRdxdR/dx
=d/dx(13x²+26x+15)
Therefore,
dr/dx=26x+26

Marginal revenue is x=7
Therefore
dr/dx=26(7)+26
=Rs.208