A company makes desks, coffee tables, and corner tables. Each item uses units of wood, fabric, and stuffing. Desks use 50 units of wood, 40 units of fabric, and 45 units of stuffing.
Coffee tables use 30 units of wood, 15 units of fabric, and 10 units of stuffing.
Corner tables use 5 units of wood, 5 units of fabric, and 5 units of stuffing.
There are 690 units of wood, 620 units of fabric, and 510 units of stuffing available to make the items.

Which three equations are needed to find the largest number of x desks, y coffee tables, and z corner tables that can be made?