From a grammatical point of view, the phrases:
"οὐκ ἀπεστάλην εἰ μὴ εἰς τὰ πρόβατα τὰ ἀπολωλότα οἴκου Ἰσραήλ". (Matthew15v24)
and " οὐκ ἔστι καλὸν λαβεῖν τὸν ἄρτον τῶν τέκνων καὶ βαλεῖν τοῖς κυναρίοις". (Matthew15v26)
could be questions. In Greek, statements and questions can have exactly the same structure. Only the punctuation marks (in written speech) or the coloring of the voice (in oral speech) differentiate a statement from a question.
However, in the specific context that you asked me about, only a theologian could give you a safe answer, considering the content and the interpretation of the text.