Advanced MathMediumQuadratic equations
Advanced Math practice question
What are the solutions to x² − 5x + 6 = 0?
- A. x = 1 and x = 6
- B. x = 2 and x = 3Correct
- C. x = −2 and x = −3
- D. x = −1 and x = 6
Answer: B. x = 2 and x = 3
Factor: (x − 2)(x − 3) = 0, so x = 2 or x = 3. The product of the roots is 6 and the sum is 5 — that instantly rules out the negative options.
Why the other answers are wrong
- A. x = 1 and x = 6
- 1 and 6 multiply to 6 but add to 7, not 5 — you need two numbers with product 6 and sum 5, which are 2 and 3.
- C. x = −2 and x = −3
- You got the right pair of numbers but the wrong signs: (x − 2)(x − 3) gives x = 2 and x = 3, and negative roots would make the middle term +5x.
- D. x = −1 and x = 6
- These don't satisfy the equation — you need roots with product 6 and sum 5, and −1 and 6 give product −6 and sum 5.
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