1. In the linear system ╥5x + 4y = 9╙ and ╥3x + 2y = 19╙, is it best to start by eliminating x first or y first? (You can try both ways.) Is there any way you can tell by inspection which is the best variable to eliminate first?
2. Try to tell by inspection which variable should be eliminated first from the linear system ╥3x + 8y = -4╙ and ╥2x + 5y = 5.╙
3. Solve the linear system ╥x + Ay = B╙ and ╥x + Cy = D╙ by substitution, and write the solution for x and y in terms of A, B, C, and D. Are there any restrictions on the values of A, B, C, and D?
