Question 1014682
{{{N^2-6N -7}}} = {{{2N(N-7)}}}
{{{N^2-6N-7}}} = {{{2N^2-14N}}}
collect like terms and equate to zero
{{{N^2-2N^2-6N+14N-7 = 0}}}
{{{-N^2+8N-7 = 0}}}
multiply through by -1
{{{N^2-8N+7 = 0}}}
{{{N^2-N-7N+7 = 0}}}
{{{N(N-1)-7(N-1) = 0}}}
{{{(N-1)(N-7) = 0}}}
{{{N-1 = 0  or  N-7 = 0}}}
{{{N = 1  or  N = 7}}}
{{{N = 1  or  7}}}