Determine whether the system x + y = 2 and 2x + 2y = 5 is consistent or inconsistent.
Solution
Problem
Determine whether the system x + y = 2 and 2x + 2y = 5 is consistent or inconsistent.
Step 1: Write the augmented matrix.
The system becomes:
[[1, 1, 2], [2, 2, 5]]
Step 2: Eliminate the first entry in row 2.
Use:
R2 → R2 - 2R1
Calculate the new row:
2 - 2(1) = 0
2 - 2(1) = 0
5 - 2(2) = 1
The matrix becomes:
[[1, 1, 2], [0, 0, 1]]
Step 3: Interpret the second row.
The second row represents:
0x + 0y = 1
or simply:
0 = 1
This is impossible.
Step 4: State the conclusion.
Because row reduction produces a contradiction, the system has no solution.
A system with no solution is called inconsistent.
Therefore, the system is inconsistent.
Result
The system is inconsistent; there is no solution.