El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left(9 x^{2} - 6\right) e^{3 x} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\sqrt{6}}{3}$$
$$x_{2} = \frac{\sqrt{6}}{3}$$
Solución numérica$$x_{1} = -80.9285718844946$$
$$x_{2} = -98.9169634472902$$
$$x_{3} = -54.9599714612626$$
$$x_{4} = -102.914960261393$$
$$x_{5} = -62.9473325059996$$
$$x_{6} = -50.9679258928336$$
$$x_{7} = -40.9954700250844$$
$$x_{8} = -0.816496580927726$$
$$x_{9} = -15.3217106782129$$
$$x_{10} = -106.913113486814$$
$$x_{11} = -72.9356912729677$$
$$x_{12} = -17.2461690329372$$
$$x_{13} = -13.4369047011233$$
$$x_{14} = -66.9422283571072$$
$$x_{15} = -37.0112595733043$$
$$x_{16} = -68.9399140192759$$
$$x_{17} = -31.0439568243175$$
$$x_{18} = -48.9724409562448$$
$$x_{19} = -58.9531872424196$$
$$x_{20} = -60.9501560614126$$
$$x_{21} = -86.9241391858771$$
$$x_{22} = -78.9302082521321$$
$$x_{23} = -39.002904504582$$
$$x_{24} = -84.9255432765689$$
$$x_{25} = -33.0315148424422$$
$$x_{26} = -44.9828136964663$$
$$x_{27} = -27.0755612809912$$
$$x_{28} = -11.6390063353452$$
$$x_{29} = -52.9637842382499$$
$$x_{30} = -94.9191438005608$$
$$x_{31} = -29.0584530466773$$
$$x_{32} = -42.9888116553855$$
$$x_{33} = -46.9773823923377$$
$$x_{34} = -82.9270189685161$$
$$x_{35} = -70.9377390683091$$
$$x_{36} = -64.9446959349238$$
$$x_{37} = -100.915941086414$$
$$x_{38} = -35.0207180637527$$
$$x_{39} = -96.9180300403546$$
$$x_{40} = -19.1925173586317$$
$$x_{41} = 0.816496580927726$$
$$x_{42} = -76.9319349875298$$
$$x_{43} = -74.9337597931602$$
$$x_{44} = -92.9203079284836$$
$$x_{45} = -23.1210889005298$$
$$x_{46} = -104.914018490736$$
$$x_{47} = -25.096062952845$$
$$x_{48} = -88.9228016067978$$
$$x_{49} = -21.1523419124891$$
$$x_{50} = -56.9564498476057$$
$$x_{51} = -90.9215259210752$$