Suppose that the functions f and g are defined for all real numbers x as follows. f(x)=3x^2 g(x)=2x write the expressions for (f*g)(x) and f-g(x) and evaluate f+g(−2).

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document