The total revenue function R(x) = x + 2x³ - 3· 5x². Find the point where marginal revenue curve…

Reading the printed $3\cdot5x^2$ as $3.5x^2$: $R(x) = x + 2x^3 - 3.5x^2$. $MR = \frac{dR}{dx} = 1 - 7x + 6x^2$ Cutting the $y$-axis ($x = 0$): $MR = 1$, so the point is $(0, 1)$. Cutting the $x$-axis ($MR = 0$): $6x^2 - 7x + 1 = 0 \Rightarrow (6x - 1)(x - 1) = 0$, so $x = \frac16$ or $x = 1$.