2.
\((1)\)使分式\(\dfrac{1}{x-3}\)有意义的\(x\)的取值范围是___.
\((2)\)若\(x-y=2\),\(xy=3\),则\(x^{2}y-xy^{2}=\) .
\((3)\)已知关于\(x\)的方程\(2x+a=x-7\)的解为正数,则实数\(a\)的取值范围是_______.
\((4)\)如图,\(M\)是\(\triangle ABC\)的边\(BC\)的中点,\(AN\)平分\(∠BAC\),\(BN⊥AN\)于点\(N\),延长\(BN\)交\(AC\)于点\(D\),已知\(AB=10\),\(BC=15\),\(MN=4\),则\(\triangle ABC\)的周长为_______.