Question

Let n be a postive integer, then n+1 is the next integer.

sum the squares of those noumbers:
n^2 + n^2 + 2n +1=85

solve for n.

so this is what i did.

n^2+2n+1=85
n^2+2n=85-1
n^2+2n=84
n=7056+4n