how do you solve k (k+1)-60

Question

It will have a negative and positive answer

Answer 1

Turn this into an equation: k²+k=60, so that we can find the zeroes or roots.

k²+k+¼=60+¼,

(k+½)²=60.25,

k+½=±√60.25=±7.7621 approx, 

k=-½±7.7621=7.2621 or -8.2621.

If your question had been k(k+1)-600, the answer would have been:

k²+k-600=(k+25)(k-24), so k=-25 or 24. (I think this might have been the expected answer so the question wasn't quite right.)