AlgebraEasy–MediumSelecting the ordered pair that solves a system
Algebra practice question
Which ordered pair (x, y) is the solution of the system y = 2x − 3 and x + y = 9?
- A. (4, 5)Correct
- B. (5, 4)
- C. (3, 3)
- D. (6, 9)
Answer: A. (4, 5)
Substitute: x + (2x − 3) = 9 → 3x = 12 → x = 4, y = 5. Check: 4 + 5 = 9. ✓
Why the other answers are wrong
- B. (5, 4)
- (5, 4): 2(5) − 3 = 7, not 4.
- C. (3, 3)
- (3, 3): 2(3) − 3 = 3 ✓ but 3 + 3 = 6, not 9.
- D. (6, 9)
- (6, 9): 2(6) − 3 = 9 ✓ but 6 + 9 = 15, not 9.
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