Difficulty: Easy
Correct Answer: 25/12
Explanation:
Introduction / Context:
A quadratic has equal real roots exactly when its discriminant is zero. We compute the discriminant for 3x^2 − 5x + P and set it to zero to find P.
Given Data / Assumptions:
Concept / Approach:
Δ = b^2 − 4ac = (−5)^2 − 4*3*P. Set Δ = 0 and solve for P.
Step-by-Step Solution:
Verification / Alternative check:
With P = 25/12 the quadratic becomes 3x^2 − 5x + 25/12 = 0. Completing the square confirms a repeated root.
Why Other Options Are Wrong:
Common Pitfalls:
Arithmetic slips with 4ac or sign errors when b is negative. Always compute Δ carefully.
Final Answer:
Discussion & Comments