as Find the point of diminishing returns (xy) for the function RX) = -0.42? +26x? +7x where R(x) represents revenue (in thousands of dollars) and x represents the amount spent on advertising (in thousands of dollars) The point of diminishing returns occurs at approximately Cur (Type an ordered pair. Do not round until the final answer. Then round to two decimal places as needed) redit OK Enter your answer in the answer box and then click Check Answer All parts showing