3/x^2-25-6/x 5(Divided by)7/x-5 4/x^2-25

You seem to be missing either a set if parentheses or an operator - specifically between the '5' and the '4/x^2' term. Or is that supposed to be 54/x^2? Perhaps this is what you mean:


\frac {\frac 3 {x^2} -25 - \frac 6 x} {\frac 7 x - \frac {54} {x^2} -25}


I suggest you start to simplify by multiplying both the numerator and denominator by x^2. See where that takes you.