Utility labor-leisure sum plz help

[MANISH]

Utility function between leisure L (hours/week) and earned income Y (Rs/week) of a person is given by
 U= 15LY – 100 L – 140 Y – 25L^2 – 2Y^2. Find the optimum values of L and Y and hence determine the implied wage rate

[Ankit Agrawal]

Are you sure the utility function is right?

Because you cannot get a positive Utility value with this equation.