We will call this positive integer x.
We will call the other integer y.
x=2y-4
x2+y2=772
We are looking for only integer solutions to the following equations.
First, plug in the first equation into the second,
(2y-4)2+y2=772
4y2-16y+16+y2=772
5y2-16y+16=772
5y2-16y-756=0
Use the quadratic formula:
y = 16±√(256-4(5)(-756))/(10)
y=(16±124)/(10)
We only want positive integers,
y=(16+124)/10
y=14
Plug back into the first equation,
x=2(14)-4
x=28-4
x=24.
Therefore, the two positive integer solutions to this system of equations are x=24 and y=14.