The positive difference between the cubes of two positive consecutive integers is equal to 1801. Find these integers. Begin your solution by denoting them k and k + 1
( k+1)^3 - k ^3 = 1801
k^3 + 3k^2 +3k+1 - k^3 = 1801
3k^2 + 3k -1800 = 0
k^2 + k -600 = 0 Qudratic formula shows k= 24 (the positive answer) then k+1 = 25