I think its not a correct solution of given equations.
Use the identity:-
a^2 + b^2 = (a + b)^2 - 2ab
Plugging in the given values;-
a^2 + b^2 = 6^2 - 2*7 = 36-14 = 22 Answer
There are no numbers without decimals which multiply to 78 and add up to 17.
4:6
6:9
12:18
And it goes on
