Which two square numbers have a difference of 51?

Suppose the numbers are A2and B2Then A2- B2= 51

that is, (A + B)*(A - B) = 51

so A + B = 51 and A - B = 1 which gives A = 26 and B = 25

or A + B = 17 and A - B = 3 which gives A = 10 and B = 7

The square numbers are, therefore, (676, 625) or (100, 49)