Question 324606
[xy]=n
{{{(x+y)^2=10y+x}}}
x and y cant = 0 but can be 1-9
x+y=2^2=4 nope has only 1 digit
x+y=3^2=6 nope has only 1 digit
x+y=4^2=16: y=1 x=6 x+y=7 nope the sum doesnt equal the original sum
x+y=5^2=25: y=2 x=5 x+y=7 nope the sum doesnt equal the original sum
x+y=6^2=36: y=3 x=6 x+y=9 nope the sum doesnt equal the original sum
x+y=7^2=49: y=4 x=9 x+y=13 nope the sum doesnt equal the original sum
x+y=8^2=64: y=6 x=4 x+y=10 nope the sum doesnt equal the original sum
x+y=9^2=81: y=8 x=1 x+y=9 yes!!!
x+y=10^2=100 nope has 3 digits

by process of elimination
x=1 y=8
check to make sure:
{{{(x+y)^2=10y+x}}}
{{{(1+8)^2=10(8)+1}}}
{{{9^2=81}}}
{{{81=81}}}
correct