Question 411189
The dimensions of the picture + mat is
{{{9 + 2x}}} x {{{21 + 2x}}} where {{{x}}} is the 
width of the border on each side
given:
{{{(9 + 2x)*(21 + 2x) = 325}}} in2
{{{ 189 + 42x + 18x + 4x^2 = 325}}}
{{{4x^2 + 60x - 136 = 0}}}
{{{x^2 + 15x - 34 = 0}}}
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{a = 1}}}
{{{b = 15}}}
{{{c = -34}}}
{{{x = (-15 +- sqrt( 15^2 - 4*1*(-34) ))/(2*1) }}} 
{{{x = (-15 +- sqrt( 225 + 136 )) / 2 }}}
{{{x = (-15 +- sqrt( 361)) / 2 }}}
{{{x = (-15 + 19)/2}}}
{{{x = 2}}}
The border is 2 in wide
check answer:
{{{(9 + 2x)*(21 + 2x) = 325}}}
{{{(9 + 2*2)*(21 + 2*2) = 325}}}
{{{(9 + 4)*(21 + 4) = 325}}}
{{{13*25 = 325}}}
{{{325 =325}}}
OK