Quantrex Academy · Free NDA PYQ solutions
NDA Mathematics Quadratic Equation 2025 NDA 2025 (Phase 2)

NDA Mathematics Question (2025) — Solution

Question

For the following two (02) items: Let f(x) = ax^2 + bx + c be a quadratic polynomial such that f(1) = f(4) = 2. Further, 2 is a root of f(x) = 0. What is the other root of f(x) = 0?

Options

  1. A. 1
  2. B. 2
  3. C. 3
  4. D. Cannot be determined

Answer

C. 3

Step-by-step solution

Given f(1) = f(4) = 2, the quadratic polynomial can be written as f(x) = a(x-1)(x-4) + 2. Since 2 is a root of f(x) = 0, we have f(2) = 0. Substituting x = 2 in the expression for f(x): a(2-1)(2-4) + 2 = 0 a(1)(-2) + 2 = 0 -2a + 2 = 0 a = 1 Thus, the polynomial is f(x) = 1(x-1)(x-4) + 2 = x^2 - 5x + 6. To find the roots of f(x) = 0, we solve x^2 - 5x + 6 = 0. (x-2)(x-3) = 0 The roots are x = 2 and x = 3. The other root is 3. Answer: 3

Practice more on Quantrex App →

Related: Mathematics — Quadratic Equation · All PYQ Banks