$11 \times 468 \div 26 = ? + 8$

The sum of squares of two numbers is $68$ and the square of their difference is $36$. The product of the two numbers is

$\frac{(0.188+0.077)^{2}+(0.188-0.077)^{2}}{0.188 \times 0.188+0.077 \times 0.077} = ?$

$(\sqrt{4489}-\sqrt{2601})=(?)^{2}$

The difference between a two-digit number and the number obtained by interchanging the digits is $36$. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is $1:2$?

$(2+\sqrt{5})^{2}=?+4 \sqrt{5}$