N-8=21 should be the answer
The answer is 6. 15 triples with 9 and 12
If the signs of the rational numbers are the same, you add them, i.e. ++ or --.
If they are different, you subtract them, i.e. +- or -+
√((x^6)/(y^4))
x^6 indicates x to the sixth power, the same goes for y^4.
