AlgebraMediumSystem with a fractional coordinate
Algebra practice question
In the system 3x − 2y = 7 and x + 2y = 9, what is the value of y? (Enter your answer as a fraction or decimal.)
Answer: 5/2 or 2.5
Adding the equations eliminates y: 4x = 16, so x = 4. Then 4 + 2y = 9 gives 2y = 5, so y = 5/2.
Common wrong answers
- If you answered 1
- Check: x + 2y = 4 + 2 = 6 ≠ 9. Solving gives y = 5/2.
- If you answered 4
- 4 is x; substitute into x + 2y = 9 to find y = 5/2.
- If you answered 5
- 5 is 2y; halve it for y = 5/2.
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