A.) Given that
![\sqrt{x^2+y^2=5}](https://tex.z-dn.net/?f=%5Csqrt%7Bx%5E2%2By%5E2%3D5%7D)
, then
![x^2 + y^2 = 5^2 = 25](https://tex.z-dn.net/?f=x%5E2%20%2B%20y%5E2%20%3D%205%5E2%20%3D%2025)
x, y can take the value of-4, -3, 3, 4
Required ordered pairs are (-4, -3), (-4, 3), (-3, -4), (-3, 4), (3, -4), (3, 4), (4, -3), (4, 3).
Therefore, there are 8 ordered pairs (x, y) of integers.
b.) Given that
![\sqrt{x^2+y^2+z^2}=7](https://tex.z-dn.net/?f=%5Csqrt%7Bx%5E2%2By%5E2%2Bz%5E2%7D%3D7)
, then
![x^2 + y^2 + z^2 = 7^2 = 49](https://tex.z-dn.net/?f=x%5E2%20%2B%20y%5E2%20%2B%20z%5E2%20%3D%207%5E2%20%3D%2049)
x, y, z can take the value of -6, -3, -2, 2, 3, 6
Required ordered pairs are (-6, -3, -2), (-6, -3, 2), (-6, -2, -3), (-6, -2, 3), (-6, 2, -3), (-6, 2, 3), (-6, 3, -2), (-6, 3, 2) . . .
Therefore, there are 8 x 6 = 48 ordered triples (x, y, z) of integers.