4. Without doing any calculations, explain why A must have an inverse but B must not: (20 points) 1 1 1 A = 05 B = 0 7 3 5. Find the inverse of the following matrix: (20 points) NON ood 0 6. In Question 14 of the Unit 4 homework, you explored a problem of finding a production schedule for a furniture manufacturer that makes tables, chair and sofas, where each product requires different amounts of resources according to the following table (in arbitrary units): Table Chair Sofa Wood 3 Upholstery CO NO Labor NO If the company has available 270 units of wood, 180 units of upholstery and 360 units of labor, what production schedule would perfectly utilize all resources? (20 points)