t\int_{4}^{9} 6/x\sqrt{x}\frac{\mathrm{d} }{\mathrm{d} x} \int_{4}^{9} 6/x.x^{1/2}\frac{\mathrm{d} }{\mathrm{d} x} \int_{4}^{9} 6.x^{3/2}\frac{\mathrm{d} }{\mathrm{d} x} [-12.x^{1/2}]^9 (then \, base\, 4) now\: sub\, in \, x =(-54)-(-24) =-30
you'd just have to double check my answer but i...