Practice question · Select all that apply
Select every system below that is INCONSISTENT, meaning it has no solution.
Hints
- Scale one equation to match the other's coefficients, then compare the constants.
- Tripling x + 2y = 4 gives 3x + 6y = 12, not 7.
Show the answer
- A. x - y = 0 and x - y = 5
- C. x + 2y = 4 and 3x + 6y = 7
- E. x + y = 1 and x + y = 2
Why
Options 1, 3 and 4 demand that the same expression equal two different numbers, which is impossible. Option 2 is the same equation doubled on both sides, consistent, with infinitely many solutions. Option 5 is a perfectly ordinary unique solution. Matching coefficients but mismatched constants is exactly the signature of inconsistency.
Practise Systems of Linear Equations
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