- A22
- B13
- C19
- D10
Step-by-Step Solution
α + β = −4 and αβ = 3, so α² + β² = αβ = 16 − 6 = 10. Check: the zeroes are −1 and −3, and 1 + 9 = 10 ✓. Answering 22 adds 2αβ instead of subtracting it; 13 subtracts αβ only once instead of twice.
Answer: D) 10
If α and β are the zeroes of , find α² + β².
Class 10PolynomialsAlgebra — Polynomials
Key idea: Geometric meaning of zeros
Zeros of are exactly the **-coordinates where the graph meets the -axis**.
- **Linear** = ax + : graph is a straight line, crosses -axis ONCE → exactly 1 zero.
- **Quadratic** : graph is a parabola. Possible cases:
- Crosses -axis at 2 points → 2 distinct real zeros.
- Touches -axis at 1 point → 1 repeated zero (vertex on -axis).
- Does not meet -axis → no real zeros.
- **Cubic** + …: shape is a curve that crosses 1, 2, or 3 times → 1, 2, or 3 real zeros.
So 'find the zeros' is the algebraic version of 'find where the graph crosses the -axis'.
- **Linear** = ax + : graph is a straight line, crosses -axis ONCE → exactly 1 zero.
- **Quadratic** : graph is a parabola. Possible cases:
- Crosses -axis at 2 points → 2 distinct real zeros.
- Touches -axis at 1 point → 1 repeated zero (vertex on -axis).
- Does not meet -axis → no real zeros.
- **Cubic** + …: shape is a curve that crosses 1, 2, or 3 times → 1, 2, or 3 real zeros.
So 'find the zeros' is the algebraic version of 'find where the graph crosses the -axis'.
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