Cubic Polynomial Real Roots Condition
CAT 2023 Slot 1 · Quantitative Ability · Hard · Algebra
This is a hard Quantitative Ability question from the CAT 2023 Slot 1 paper. It tests Algebra. The full answer key and a step-by-step explanation are below — try it yourself first, then reveal the solution.
The equation has as one of the roots. If the other two roots are real, then the minimum possible non-negative integer value of is
2
Explanation
Since is a root, factor out :
For the remaining quadratic equation to have real roots, its discriminant must be non-negative: This gives two cases:
We need the minimum possible non-negative integer value of . For non-negative integers (), gives the smallest integer .
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