Question 109894
{{{b^2-2bc+c^2}}}

With b=5 and c=-4 the substitution will look as follows

{{{5^2-2*5*-4+-4^2}}}

Per the order of operations we need to process the exponents first

{{{5^2}}} becomes 25 and {{{-4^2}}} becomes 16

Replace in the equation
{{{25-2*5*-4+16}}}

Next simplify any multiplication.  {{{2*5*-4}}} becomes {{{-40}}}

Replace in the equation
{{{25-(-40)+16}}}  Note that there are 2 minus signs with the 40.  This will convert the negative 40 into a positive 40, thus the equation will look like this in its finality {{{25+40+16}}}

Simplify 
Your answer should be {{{81}}}

I have applied the universal simplifier and solver as well so that you can see the steps in animation.  Also, if you want to show a number raised to a power of another number use the carat symbol (shift and the number 6  (^) on your keyboard.)  Just a helpful hint.

*[invoke explain_simplification "5^2-2*5*-4+4^2"]