How many integer solutions to
x1 + x₂ + x3 + x4
x₁ ≥ 4, x2 ≥ 2, x3 ≥ 5 and x4 ≥ 3?
=
31 are there for which
![How many integer solutions to x1 x x3 x4 x 4 x2 2 x3 5 and x4 3 31 are there for which class=](https://us-static.z-dn.net/files/d67/2906691d42abc7bccc1b183df86e07d8.png)