It takes two hours for a person X to mow the lawn. Y can mow the same lawn in four hours. How long (in minutes) will it take X and Y, if they work together to mow the lawn?

The three roots of the equation f(x) = 0 are x = {-2, 0, 3}. What are the three values of x for which f(x -3) = 0?

For what values of k given below is $${{{{\left( {k + 2} \right)}^2}} \over {k - 3}}$$ an integer?

Functions F(a, b) and G(a, b) are defined as follows:
F(a, b) = (a - b)² and G(a, b) = |a - b| , where |x| represents the absolute value of x.
What would be the value of G(F(1, 3), G(1, 3))?