I notice that this expression has the form $(a + b)^2 - (a^2 + b^2)$, where $a = 25$ and $b = 8$. I recall that $(a + b)^2 = a^2 + 2ab + b^2$, so I can rewrite the expression as $(a^2 + 2ab + b^2) - (a^2 + b^2)$. Then I can cancel out the $a^2$ and $b^2$ terms and simplify to get $2ab$. Plugging in $a = 25$ and $b = 8$, I get $2(25)(8) = 400$.


What is the value of the expression $(25 + 8)^2 - (8^2 +25^2)$?