It’s best if you download Photomath
Let
x-------> the first number
y------> the second number
we know that
![x+y=31](https://tex.z-dn.net/?f=%20x%2By%3D31%20)
![x=31-y](https://tex.z-dn.net/?f=%20x%3D31-y%20)
equation ![1](https://tex.z-dn.net/?f=%201%20)
![x*y=234](https://tex.z-dn.net/?f=%20x%2Ay%3D234%20)
equation ![2](https://tex.z-dn.net/?f=%202%20)
substitute equation 1 in equation 2
![(31-y)*y=234\\ 31y-y^{2} =234\\ -y^{2} +31y-234=0](https://tex.z-dn.net/?f=%20%2831-y%29%2Ay%3D234%5C%5C%2031y-y%5E%7B2%7D%20%3D234%5C%5C%20-y%5E%7B2%7D%20%2B31y-234%3D0%20)
using a graph tool-----> to resolve the second order equation
see the attached figure
the solution is
![13 and 18](https://tex.z-dn.net/?f=%2013%20and%2018%20)