10-4 Solving Systems by Addition To solve a system you can use ________, __________, or ______ method. How do you use the addition method? 1. ____ the 2 equations together to _____ a ________. 2. Find the _____ of the _______ left. 3. _________ that _____ into one of the ________ to find the ____________.
1. Going with the wind, a blimp flies 360 miles to an air show. The trip takes 4 hours. The return trip, flying against the wind, takes 9 hours. How fast is the blimp flying in still air? What is the speed of the wind? Let b=speed of blimp in still air Let w=speed of the air d=rt or d/t=rw’s are opposites
2. Solve this system. 2x - 5y = 18 4x - 5y = -4 { They do not have opposite variables, but if you take the opposite of one equation, the y’s would become opposites. -() Solution is ( )
3. At the 1987 annual meeting of the NCTM, the system below was found on a menu card at a restaurant in California. How much did each item in column A and column B cost? Multiple Choice 2 or more entrees Choose 1 from column A and 1 from column B - $5.49 Choose 1 from column A and 2 from column B - $6.99 A B ·Chicken Dijon · Fried Chicken ·Top Sirloin Steak (2 pieces) ·Steak Dijon ·Battered Cod ·Fried Chicken ·Shrimp ·Chicken Strips A + B = $5.49 A + 2B = $6.99
Item A costs and item B costs.