(2) Assume that the company needs to print X copies of materials.

When x is less than or equal to x≤2000, the cost of printing plant A is 600+0.3x, and that of printing plant B is 600+0.3x, which is the same for both factories.

When 2000 < x ≤ 3000, the cost of printing house A is 600+0.3× 2000+0.3 (x-2000 )× 90% = 0.27x+660. The cost of printing plant B is 600+0.3x The cost of printing plant A is relatively low.

When x is greater than 3000, the cost of printing factory is 600+0.3× 2000+0.3 (x-2000 )× 90% = 0.27x+660, and the cost of printing factory is 600+0.3 (x-3000) x80% = 0.24x-65438+.