A polynomial in x whose roots are 4/3 and -3/5 can be obtained by using the fact that if r and s are the roots of a quadratic equation, then the equation can be written in the form of \(x^2-(r+s)x+rs=0\). In this case, r = 4/3 and s = -3/5. Substituting these values into the equation, we get:

\(x^2 - \left(\frac{4}{3} + \left(-\frac{3}{5}\right)\right)x + \left(\frac{4}{3}\right)\left(-\frac{3}{5}\right) = 0\)

Simplifying this expression, we get:

\(x^2 - \left(\frac{20-9}{15}\right)x - \frac{12}{15} = 0\)

Multiplying both sides by 15 to clear the fractions, we get:

\(15x^2 - 11x - 12 = 0\)

So, a polynomial in x whose roots are 4/3 and -3/5 is \(15x^2 - 11x - 12\)