I dont really get what you mean by 'simply the expressions' but if you're looking for the value of x or a version of the equation that doesn't consist of fractions,
[tex]( \frac{7}{3} x - \frac{4}{5} x^2 = 0)15[/tex]
[tex]35x - 12x^2 =0[/tex]
[tex]x(32-12x)=0[/tex]
x= 0, x= 35/12