Question:
Find two natural numbers which differ by 3 and whose squares have the sum 17.
Solution:
Let one natural number be $x$ and other $(x-3)$.
Then according to question
$(x)^{2}+(x-3)^{2}=117$
$x^{2}+x^{2}-6 x+9=117$
$2 x^{2}-6 x+9-117=0$
$2 x^{2}-6 x-108=0$
$2 x^{2}-6 x-108=0$
$2\left(x^{2}-3 x-54\right)=0$
$\left(x^{2}-3 x-54\right)=0$
$x^{2}-9 x+6 x-54=0$
$x(x-9)+6(x-9)=0$
$(x-9)(x+6)=0$
$(x-9)=0$
$x=9$
$(x+6)=0$
$x=-6$
Since, x being a natural number, so x cannot be negative.
Therefore,
When $x=9$ then even integer
$x-3=9-3$
$=6$
Thus, two natural number be 9,6