如图,在平面直角坐标系中,\(\triangle ABC\)的三个顶点分别为\(A(-1,-2)\),\(B(-2,-4)\),\(C(-4,-1)\).
\((1)\)把\(\triangle ABC\)向上平移\(3\)个单位后得到\(\triangle A_{1}B_{1}C_{1}\),请画出\(\triangle A_{1}B_{1}C_{1}\)并写出点\(B_{1}\)的坐标;
\((2)\)已知点\(A\)与点\(A_{2}(2,1)\)关于直线\(l\)成轴对称,请画出直线\(l\)及\(\triangle ABC\)关于直线\(l\)对称的\(\triangle A_{2}B_{2}C_{2}\),并直接写出直线\(l\)的函数解析式.