4. (25 marks) An assembly plant for high-definition televisions makes two types of TVs. Model X is aimed at the price-sensitive market and has a net value (i.e. after subtracting all variable costs) when leaving the plant of $150 per television. Model Y is 4K with many more features; its net value is $450 per television. Each Model X requires 6 labour-hours in assembly-line 1, and 4 labour-hours in assembly-line 2. Each Model Y requires two labour-hours in assembly-line 1, and 7.5 labour-hours in assembly-line 2. Each week assembly-line 1 is available for 6600 labour-hours, and assembly-line 2 is available for 8930 labour-hours. At least 40% of the total production must be of Model Y; however, they cannot sell more than 940 units of Model Y. (a) Formulate a linear optimization model for this situation. Write every constraint in standard form (