- A6
- B−6
- C11
- D−11
Step-by-Step Solution
For a cubic with , the product of the zeroes is −. Here , so and . Check: ✓. Answering 6 forgets the minus sign in −d/a; 11 is the value of q, not .
Answer: B) −6
The zeroes of the cubic are 1, 2 and 3. What is ?
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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