That is equivalent to solving {{MATH_19}} {{CMD_20}} {{CMD_21}} let's solve the equation {{MATH_22}} {{MATH_23}} {{MATH_24}} {{MATH_25}} Divide by {{MATH_26}}. {{MATH_27}} Solve for {{MATH_28}}. How do we know that the function {{MATH_29}} has a maximum at this point? {{CMD_30}} {{MATH_31}}