The systems in Exercises 1 and 2 exhibit a lower triangular pattern that makes them easy to

Question:

The systems in Exercises 1 and 2 exhibit a "lower triangular" pattern that makes them easy to solve by forward substitution. (We will encounter forward substitution again in Chapter 3.) Solve these systems.
1. x = 2
2x + y = -3
-3x -4y + z = -10
2. x1 = -1
-1/2 x1 + x2 = 5
3/2 x1 + 2x2 + x3 = 7