Prove that: d) there do not exsist integers m abd n such that 12m+15n=1 f) if there exist integers m and n such that 12m+15n=1, then m and n are both positive. so far for d i have d) since 12m is always a multiple of 3 and since 15n is always a multiple of 3, then adding or subtracting two multiples of 3 always yields another multiple of 3, and so 12m + 15n can never equal 1 (it can only equal multiples of 3.) but I have no idea how to do f. In the back of the book it has a hint that says, "See the statement of part (d). Can you prove that m and n are both negative whenever the antecedent is true?" I don't understand it. Can you please help me? Thanks for the help!