Rewrite the entire sentence replacing the indirect object with an indirect object pronoun.
Nosotros hablamos por teléfono con la <u>maestra</u>.
Answer : Nosotros le hablamos por teléfono.
Explanation: The indirect object is "la maestra", that is third singular person, so the indirect object pronoun has to be in the third singular person too, "le".
Hope this helps!
no se yo soy,
no sé, espero ser o no, no sé byee