Advanced MathVery hardTangent line meeting a parabola once
Advanced Math practice question
The system of equations y = x² − 4x + 3 and y = 2x − 6 has exactly one solution (x, y). What is the value of x?
Answer: 3
Setting the right sides equal: x² − 6x + 9 = 0, so (x − 3)² = 0 and x = 3.
Common wrong answers
- If you answered 0
- 0 is y at the solution, not x.
- If you answered 1
- 1 is a zero of the parabola but does not lie on the line (2 − 6 = −4 ≠ 0).
- If you answered -3
- −3 comes from a sign slip in (x − 3)².
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