Question 880780
{{{(A+B)^2=A^2+2AB+B^2}}}
{{{(A-B)^2=A^2-2AB+B^2}}}
{{{(A+B)^2-(A-B)^2=A^2+2AB+B^2-A^2+2AB-B^2}}}
{{{(A+B)^2-(A-B)^2=4AB}}}
{{{(A-B)^2=(A+B)^2-4AB}}}
Substituting,
{{{(A-B)^2=25^2-4(252)}}}
{{{(A-B)^2=625-1008}}}
{{{(A-B)^2=-383}}}
There's a problem here since the square of a real number cannot equal a negative number.
Re-check your problem setup and repost your question.